Stats:
Magic. Constitution. Willpower. Cunning.
Roughly in that order. Always cap out Magic. Always build up at least some Constitution-surprise attacks are what is killing you, not anything else. Willpower is good if you need more Mana, but remember that you'll be finding Willpower on items incidentally, and that you don't need much currently stored for some builds-it varies a lot on the build how much of this you need. Cunning is the remainder stat-crits are how you do real damage as an Archmage, but you need Constitution and Willpower for some builds, period, and you have to make the damage cut to get them.
Races:
-Higher is great for Arcane builds, or builds that plan on utilizing Aether Permeation later. Since that's a pretty good skill, Higher is a pretty good go-to race. Downside: You want as much HP as you can get, and Higher's 11 is not that.
-Cornac doesn't bring much to the table. If you're going for more than two unlocked Class categories, you're probably spreading your Class points too thin anyways. 6 HP Mod total and fast leveling speed isn't unusable, but there's very little point to this combo.
-Halfling is good. 8 HP mod and anti-physical/anti-Stun skills! Decent leveling rate! Good option.
-Dwarf is kinda weird. The main reason would be for saves-if you find you have status problems in general, or with Archmage in specific, go with it. I didn't, and I played a Skeleton, but if you do...
-Shalore is bad. +10% critical hit rate is a nice skill, reactive invis and a Haste skill(...that scales off Dex, so you're not getting the most out of it) are nice...but Timeless is mostly a status cure for you (Or a Shielding duration extender, I suppose, but one of your shields lasts insanely long, another is iffy to extend and standard damage shields simply aren't likely to stand up 10 turns, even repeatedly boosted, against anything that matters.), and 5 HP Mod is terrible. I'd take it over Cornac probably, but as an Archmage, your main cause of death will be the things you don't see coming. No need to make that worse with more terrible HP than you need to put up with.
-Thalore is probably pretty decent, granting you a physical save option and some nice resists. 7 HP Mod like Higher is okay too. I'd prefer Halfling-faster leveling is nice-but it depends on what you want I suppose.
-Skeleton is pretty classically amazing. If, for some reason, you really need all of the category points ever, this is a better option than Cornac, as you can easily ditch an inscription slot here, and you're surprisingly flexible on the Generic end. Bone Shield with Shielding and Aegis is just this side of invulnerability, as long as you see the threat coming and it doesn't last longer than the shield, and Resilient Bones/Reassemble are always nice. Usually considered the best/OP/etc. option.
-Ghoul is surprisingly good with niche builds. 10 HP Mod Archmage-same as a Higher Alchemist or Cornac Rogue-is very, very hard to drop, and Temporal can cure their speed woes. On the other hand, it's hard to imagine using one without Temporal, as otherwise you can eat brutal damage bursts thanks to the speed. So, you have to build around the Ghoul.
-Yeek Archmages don't exist.
To update on this: After the initial posting of this, several people tried out-and liked quite a bit, and cleared with-Yeek Archmages.
The best thing I can say based on assessments of these is that they're good for players with high skill, or high luck. They have extremely horrible HP(L50 with heavy Con building will still be 200-300 below 1000), but the added speed, when combined with Essence of Speed, makes for a character that is often in control of a situation, and Archmage is quite strong when in control of the situation. Falling asleep at the wheel will get you killed, but if you're constantly sharp-or just lucky and get a lot of good +life or few nasty blindside situations-you can do pretty well, it seems. It's not nearly as bad as I expected, from reports.
General builds:
As a rule, you want to think in terms of an element and a support category, for your unlocks. You want five Runes/Infusions for status curing, barriers, etc., but that's more of a later thing(And you can substitute one of the five for Celestial/Light if you prefer). The important thing is that you pick up advanced categories, though, and build around them.
Then, you will want to make some investments for support effects and attacks to shore up holes or make your life easier, within these main builds.
Here's some thoughts about the possible builds and my personal feelings on them...
Main categories:
-Wildfire. Classic good build, has gotten better recently since it no longer requires Meta. 5ing Wildfire(the actual skill) will cause you to so heavily resist your own fire that it's nearly negligable/is actually beneficial thanks to Cleansing Flames(even better if you have Fire Affinity!). Basically blast things with the excellent Fire skills and then produce large DoTs every single time that debuff enemies and remove your negative status.
The downside is, well, you have to unlock it, if you're not just hacking your unlocks open. Many players have issues getting it. However, I have seriously seen people clear 5/5/5/5 5/5/5/5 Fire/Wildfire builds with very little extra support. Fire is good.
Combines with: Meta used to be classic, to avoid your own fire damage. It's still an okay option, more for Quickened Spells(For more Fire spam) than before. You can go with Temporal for Essence of Speed or just grab an extra Generic category, even.
However, my personal favorite support for this is Storm. Storm makes a surprisingly good support category-1/5/5/(0 or 5 depending on your preference and how much investment you have in Air) will give you a surprisingly good attack for nuking any dangerous crowd, in the form of Nova and Hurricane. Applying a massive radial damage over time effect to anyone that can be stunned is amazingly good, and for ten points, this makes a really good support effect to Fire's general slugfesting balance.
-Storm. Has improved a lot, thanks to Tempest recently allowing any Lightning attack to daze(and hence, add Hurricane). Hurricane is basically amazing-an area of effect, extremely high damage, damage over time effect. Hit two people side by side? Well, they both basically take double. Hit five? Marvel as they vaporize. It's pretty fun. It's the main trick of the tree-downside is, Stun resistance shuts it down, and Air/Storm are not that great at direct damage. Oh, and Hurricane can't hurt you, so you don't need Spellcraft out of Meta, either.
The other thing is Thunderstorm. It consumes a ton of Mana, but it's essentially crowd clear heaven, doing constant area of effect strikes. The best use for this is with Mana on critical hit weapons, as the bolts refund mana. (Hint hint Staff of Archmage Tarelion, AKA the best Archmage weapon in the game, hint.)
Also, this is an easy unlock, so most people have this.
Combines with: You'll want some support tricks (I'm getting there, really!), but the main combo for this is Wildfire, to me, as mentioned before. You can do a heavy Wildfire build that uses Hurricane and Nova as a support, or you can do Lightning/Chain Lightning/Thunderstorm/Tempest/Hurricane/optionally Nova heavy builds, and then shore it up with some basic Flame/Fireflash and 1/1/1/5 Wildfire. Either way is good.
If you don't have Wildfire, things become dicier. Temporal and Meta both fail to combine well. Aether's probably your best bet, but Aether's best with Meta. Sorta a weird situation, there.
-Aether. The relatively new spellset. There's good news and bad news here-the bad news is that Pure Aether causes Disruption Shield's manastorm, if you screw up and let it form, to blow you up much, much better. The good news is that Aether Avatar and Aether Breach are pretty much amazing-the former is a great buff to all your Arcane focused skills, and the latter is essentially a smaller Fireflash that blasts the same area repeatedly.
Generally speaking, I find Wildfire a little better from the on paper-sadly, my run of Archmage was before this got put in, though I know the stats. But it's still good, and importantly, it starts out unlocked, so that newer players can actually use it.
Combines with: Meta. As far as I'm aware of, both Aether Beam and Aether Breach are good ways to kill yourself without Spellcraft, and Spellcraft's useful in general. There's some use for Temporal+Aether Avatar if you're feeling dangerous, though-Aether Avatar gives you insanely fast cooldowns, and Essence of Speed lets you take advantage of them. Just don't blow yourself up. No real point in not taking one of those two(A Skeleton could possibly get away with both, as could a Ghoul).
-Ice. Sorta relatively weaker than the other options, and best used for very, very tanky Archmages, which is generally a contradiction in terms. Looks good on a Ghoul, though. The big thing is that Shivgoroth gives you lots of Cold affinity, which in turn means that, as long as you don't fatally hit yourself, you can heal tons off your own attacks. The fatally is pretty important, though, as I believe the heal comes after and you die if you go below 0 from the hit.
Be careful! Probably not a good beginner build, which is fine as you probably don't have this unlocked anyways.
Within all of that, Freeze is a brutal nuke of a spell if heavily boosted(by, say, Uttercold), and hitting yourself with Ice Shards and Glacial Vapours is a heck of a lot of healing(though, it works best without Uttercold, due to resistance penetration from it. Sorta a catch 22.).
Combines with: Not Meta. You want to hit yourself. All the time. Temporal's probably your best bet, or Storm. Temporal/Ice Ghoul is something I'm pretty tempted to try at some point...
-Stone. Don't use Stone. Don't get me wrong, Stone has some good stuff-Earthen Missiles is amazingly good(probably the best CD to damage ratio of any spell, in a vacuum), Earthquake is very solid(repeatedly Stunning damage over time attack over a big area!) and...that's...it outside of Mudslide. Three spells, none with very fast cooldowns, even with Body of Stone lowering them, isn't a skillset, not really, so Crystalline Focus is iffy and you can't really buff Physical with your other elements you're running. It's not great on Archmages. Fun, but not optimal.
Combines with: Arcane Blade, Stone Warden.
Updating on this: In SVN, Earth's been changed quite substantially and Stone has been buffed marginally as well. (I think in part thanks to ideas I had initially writing this guide.
)Notably, Body of Stone is now instant, and Dig has been transformed into a 5CD physical damage ray spell that works with Body of Stone. (Stone Wall also does damage and has less CD, but this is more minor.)
As such, Earth/Stone is now much more viable. A full 5 on Body of Stone gives 2 CD on Pulverizing Auger(the Dig replacement) and 3 CD on Earthen Missiles, which allows you to mostly spam what is essentially a physical version of Mind Sear and a really powerful multiple hit bolt spell. The playstyle's very linear, but the damage on both spells is some of the best you can get, for sure. To boot, I believe that, if you can get some way to boost Stone as a category, it is possible to catpoint it again and get -4 CD on both skills, which is kinda scary.
As such, I tentatively can say that Earth/Stone's pretty good now. I don't think it competes with Fire/Wildfire, which is generally more flexible... but if you want an Archmage that hits like a Corruptor and don't mind standing still a lot, this is seriously solid, on paper. The main downside is that, since you can't run most of your relevant elements while strengthening Physical, you pretty much want to rely on Earth and Stone entirely for damage. But as long as you use Body of Stone a lot, you can do that.
-Meta. Not a focus of the class, instead is support for other spells. Has two roles: Making you not get hit by your spells(Spellcraft, which has the nice side effect of basically allowing you to constantly nuke resistances with every spell you ever use. Spellshock's fun.), and letting you cast your spells faster(Quickened Spells, generally the lesser of the two skills, but really good with Essence of Speed. Notably can produce 2 CD beams pretty easily, with any other spell cooldown lowering equipment!).
Disperse Magic is useful, too, though, don't get me wrong. Quickened Spells is probably the better option if you want an investment to give you cooldown handling, though, not Metaflow.
Combines with: See above. Best with Aether, sorta okay with Wildfire, good with Temporal.
-Temporal. Congeal Time isn't bad in theory(it's actually a piercing projectile, so it can hit more than one enemy, and it's a lot of slow at cap), Time Shield's decent enough(Lowers negative status duration, spreads out damage, generally nice enough albiet not actually something that prevents damage, only delays it), Time Prison is a good way to buy some time(albiet really expensive)...
But you're here for Essence of Speed. 60%~ Global Speed as a sustain? 250 Mana is expensive, but this is still insanely good. You don't want to combine this with a bunch of sustains, though. Avoid Storm heavy builds, and Wildfire's only good if you're not bothering much with many sustains in general.
The best combo is Quickened Spells+this though, since you'll always have spell ammo to fire at people that way-the speed's no good if you're sitting around swinging your staff at people half the time!
Support effects:
The stuff that greases the gears of your main build. The little skills that make your life easier. You can't afford all of these, obviously-so here's some thoughts on good, primary skills for this.
-Tri-beam. As L4(the beam is gained at 5 modified talent, so you need 4) Flame, L3 Manathrust and L3 Lightning is referred. You can invest more if you find yourself using this heavily. Gives you a constant ranged damage source, no matter what happens-three 3CDs means the cooldown constantly cycles, and the Mana costs on this are incredibly cheap.
This is really, really good early and mid-game. It's an extremely powerful constant barrage of damage early on, while you're getting your main setup going. The downside is, it's not that great long term-spamming your primary element is better for elemental setups(which will only make up a third, at best, of this-Cold focused setups get their own 3CD skill in Ice Shards), so once your main element gets going, this will make for a useful backup but not something you use much, at best.
Best with: Meta/Temporal. You want overkill Cooldowns with Temporal, and Meta will, with equipment luck, get you 2CD beams! Otherwise, it's useful for any setup without being incredible at any.
-Status skills. Illuminate's the bigger one here-Never is your primary element, sure...but at L5 it's decent support damage, hits a huge area, and Blind is a surprisingly good status.
Flameshock's good if you aren't Fire (It's still good for Fire. It's just even better for Fire. You want heavy invest in it, not a point or two.) or Lightning (where Storm will grant you something nearly as fatal as Stun, that runs off the same check), as well, because it's a nice area of effect Stun. There's little reason not to get at least L1 Flameshock.
You could alternatively invest heavily in Freeze instead of Flameshock, if you like more damage-same Stun resist, but does a ton more damage and has a different, more debilitating but harder to damage through, effect.
All of these stay pretty good at all points in time.
Best with: Anything, really.
-Disruption Shield.
Disruption Shield is practically a skill you can create an entire build around-it makes consuming more mana better in a sense, since it can absorb more damage then. Fatigue becomes better if you're trying to heavily abuse this, as does huge cost skills like Thunderstorm. Take a good hard look at this at some point in your build.
Best with: Stuff that costs a ton of Mana. The more, the better. You'll want to at least 1 it no matter what, it's never bad, it's rarely even bad to 5 it, but consider your build for how much of a priority it is.
-Blur Sight.
As a general rule of thumb, Defense of 40 will cause most earlygame physical threats to miss and lategame physical threats to gain at least some miss chance. Defense of 60 will cause most lower end lategame physical threats to reliably miss and high end ones to gain a 50-50 miss rate. Bit of a rough rule of thumb of mine.
Blur Sight at 5 can grant 50~ Defense, which is enough with any old robe to hit 40, and with Defense oriented equipping in mind can hit 60.
"But I don't want to be at physical range as an Archmage! Isn't that useless?" Enemies with Rush don't care what you want. They want to Daze you and then hit you with Stunning Blow criticals, two-shotting you. This is the kind of thing you risk as Archmage.
Blur Sight's not a great defensive option, but it's better than Stone Skin for the most part(though, consider Stone Skin if you happen to run into the Wrap of Stone, I suppose.). It's worth considering.
Best with: Anything, depends on how much you value the effect.
-Fireflash.
If you're not running Fire, you're probably still running your staff in Magestaff mode. If you're Storm, you can skip this-you have plenty of crowd control. Otherwise, 5 Fireflash. It is amazing and almost certainly my favorite Archmage attack spell.
Best with: Not Storm.
As a note: I'm obviously not listing every spell here, and that doesn't mean the spells I'm not listing are bad. But these are the big support draws to me.
-Generic points.
The simple part.
Conveyance, pick which one you like better: Phase Door or Teleport, and then level one to 4(which is 5 modified talent and gets you the controlled effect, IIRC). Phase Door gives you better short range mobility when controlled, while Teleport gives you the ability to reliably appear in a safe zone after a teleport. I prefer Teleport, but it's a matter of taste. If you're really into mobility as a playstyle, consider 4ing both, there's worse ideas.
Displacement Shield is amazing, at least 3 it. Costs a ton, but it's a very long barrier that can stack with other barriers and even does some damage.
Probability Travel is a good 1 for an emergency teleport-it works in very low mana situations, or when other teleports are on cooldown-and makes for a very interesting playstyle choice if heavily leveled. I don't recommend this for a new player, though, make your own decision if you want it.
Aegis, get Shielding up to 4(for the extra turn), take Arcane Reconstruction at least to 3 and possibly to 5(depends on how much you like a heal), Arcane Shield's a good 1 no matter what and worth leveling if you are into using Healing Infusions, and Aegis(the spell) is a very good 1, and a pretty good 2-3 depending on how many shields you like to run.
Divination, Arcane Eye is a great 1(and leveling it is an option), Keen Senses is a good 3+(more spellcrits and some stuff that is less important than spellcrits!), and Vision/Premonition are worth considering but not major.
See? Simple! Not really build specific at all. You can pick up Celestial/Light off an escort, or heavily invest in your racial category.
-Prodigies.
Aether Permeation is good (lets you turn Arcane Resistance into All Resist, which is nice if you find some decent Arcane resistance pieces, and also amounts to more ways to prevent yourself from getting suddenly ganked.), Meteoric is good(though, watch out, without Meta right now the Stun can sometimes Stun yourself. It's a bug, will be fixed next version), and Cauterize and Corrupted Shell are really good protection against sudden kills.
You can grab other stuff, too, but those are the ones that strike me as the best draws off the top of my head.
-tl;dr version for a single build:
If you're a new player that just got Archmage? And you want to try one?
Go Higher, go for Lightning 1/Manathrust 3/Flame 4/Lightning 3 in that order.
Work towards getting Aether and Meta going, so you don't blow yourself up with Aether-go for Aether first, though, you can use Breach and Avatar before that, you'll probably want ?(your call, experiment with the skill some to see how much you like it) in Arcane Beam, 5 in Breach, and probably 5 Aether Avatar/Pure Aether. For Meta, 5 Spellcraft, rest of the details is your call.
Keep an eye out for Arcane resistance stuff and take Aether Permeation at 30. Pick up Cauterize at 42 for sudden kill prevention.
For Generic, heavily build the Higher skill Born Into Magic so you have Arcane resistance and damage boosting. 4/1/5/(0 or 1) in Conveyance is my suggestion for new players, (3 to 5)/(4 or 5)/1/2 in Aegis is pretty good, and 1/5/0/0 is reasonable for Divination. Pick up Combat Training in Last Hope and get Thick Skin up and running as soon as possible, as well as L1 Armor Training.
Lategame, look at those support options for more options to work with-or decide on your own support skills.
I can't promise this is an exceptional build set overall-I've cleared an Archmage, but it was a while ago, before Aether, so I know mostly the code for this. But I'm pretty confident in it, and I've seen builds that looked fairly similar clear.
It's not necessarily the best build, but it doesn't require any of the special unlock categories-Aether and Meta are both starting on an Archmage, the moment you unlock the class. So it's probably the best "out of the box" setup, outside of Meta/Temporal. I don't suggest that due to Essence of Speed's huge Mana drain, it creates a weirder curve and tempts early players to grab Essence of Speed too early, which is easily fatal.