320x240 kicks ass! 320x200 does too of course. What a reminder of good old days!
If you're considering it for a game you're making that isn't, as Van said, retro, however, you need a frontal lobotomy (or a good long talk with Quoth-The-Raven which does the same thing, only messier).
I mean, to add some persective, games released four years ago, that's in 2000, supported 1600x1200 resolution, 32 bit color, with 3d acceleration. Upcoming games-- take the new Unreal 3 technology-- support god knows how many resolutions and 64 bit color. Even 640x480 resolution is quite archaic and very rare in modern games (the HUDs just don't fit).