It'll last you a heck of a lot longer than a PS3 with its myriad of games that are actually of decent quality. Sure, theres Oblivion, but thats only 'cause Bethesda sold out and gave in to a bigger paycheck.
... And even that isn't as good on the PS3.
But assuming your mind can't be changed, go with the 60 gig one and be able to play your PS2 games. Nobody will ever need 80-160 gigs.