60 GB PS3's should actually have the PS2 chip or whatever (EMOTION ENGINE!!!!) so they should run all games with the addition of a upscaler/smoother, though I suspect the virtual memory cards are probably more prone to data corruption than physical memory cards (then again, physical memory cards and data corruption was pretty common for me). 80 GB is through emulation, so there will be games that either don't run at all or ones that have very minor to game-breaking glitches. I have the 80 GB and can play most games just fine, but some games like Ar Tonelico 2 don't run and others like Star Ocean 3have glitches that crash the game (though SO3's can be avoided). The 80 GB should play most PS2 games, but if you own only that and no PS2, it would probably be a good idea to check compatibility through various forums before you buy a new PS2 game. PS2 games do look better being played on a PS3 from my experience.
