ToME: the Tales of Maj'Eyal

Cause, y'know, otherwise they're a bit dull. Plus they look a bit silly standing around doing nothing when you can see them but they can't see you back. Let them move about randomly, add a bit of brownian motion to the map.

Or, you know, let the npcs in towns do ... anything. The towns may have people, but they may as well be statues or dead.