I'd recommend GAUNTLET: DARK LEGACY. An excellent, brain-cell killing hack-and-slash 3D version of that old late-80s arcade quarter-muncher. The only it's lacking is the disappointed voice telling you "don't shoot food" and "elf is about to die". Been out for a while, should be cheap.

CRAZY TAXI is also pretty enjoyable - straight up crazy car driving. You can play an enjoyable game in 5 minutes. On the $20 Greatest Hits label.

I'd recommend against FINAL FANTASY X. It sprawls all over the place, you have to keep track of a zillion characters and minigames and side quests, and the whole thing runs on rails. Very pretty graphics, though.