i'd say ps3 for the simple reason that the ps3 has waay more exclusives so you have a much larger library of amazing games to choose from. Also, psn being free will save you a lot of money in the long run.
as far as list wars go...ps3 games i personally loved:
demon souls, valkaria chronicles, ratchet and Clank (Tools of destruction, quest for booty, crack in time, and i'm looking forward to All 4 one), lbp 1 and 2 (although if you get lbp2 you probably don't need 1), uncharted (1 was good, 2 was amazing, looking forward to 3 very much), mod nation racers, kz (2 and 3), infamous (1 was amazing, 2 looks even better), god of war (3 and collection), heavy rain, 3D Dot game heroes, sly cooper collection.
on psn echochrome, wipeout HD, pixal junk eden and shooter, ..there are a lot of other great psn games in my collection but i'm less sure of their exclusive status.
coming out later is: twisted metal, last guardian.
move is pretty good btw: RE5 Gold edition was a blast, echochrome 2 was good, looking forward to sorcery, playstion move Heroes, sorcery, under siege.
notable multiplats not on wii (just in case you need a better case still to ditch the wii for an HD console); batman arkam aslyum, arkam city, portal 1 and 2, resident evil, assassins creed, bioshock (1 not 2), dragon age (1 and 2), mass effect (2 at least is multiplat),
