ToME: the Tales of Maj'Eyal

What do you guys use to view/modify the lua files on Windows? Just Notepad (don't seem to work too well...) or something more advanced?

Notepad++ is exceptionally good. Has syntax highlighting, an easy interface, and the ability to change tabs to blocks of spaces (great for code alignment).

I simply use luaEdit

It's made JUST for editing lua code, is very well organized, and is an intuitive design.

I'm rather fond of EMACS. It has a LUA mode (and everything else you could conceivably want in a program that deals with text). The learning curve is very roguelike:

I *love* vi/vim, but the learning curve is rather steep. Especially at the start, so most first-time-users give up when they can't even edit a simple text file...
There are loads of extensions/scripts/highlight/filetype/folding stuff for vim. So there's one for Lua as well.