Most of the persons working from my plans will be at least using MAME to play games. Jeff at Monstarcade can get you the roms you need to play the games, as well as all the Laser Disc games (think Dragon's Lair and Space Ace). I highly recommend him- he's a great guy.
Plenty of PC games run just fine on the cabinet. Pretty much whatever games you can remap the keys for will work. Tiger Woods plays fantastic on the cabinet, by the way.