Get assassins creed 2 if you haven't played that franchise, its a seriously wonderful game.
Get Demon's Souls if you like some addicting RPGs that are extreme hard.
Infamous and infamous 2 shortly.
MGS f**king 4. Best game Imo.
Uncharted 1 and 2 is an obvious must buys for every PS3 owner, at least Uncharted 2 is.