PATAPON! Seriously, just get it. It's cute, awesome, and also hard.
God of War: Chains of Olympus, It's the God of War you know and love. If you don't like GoW then don't get it.
Killzone: Liberation
Jeanne D'Arc, it's a turn-based strategy JRPG that is absolutely fun if you're into the JRPG's
and FFVII: Crisis Core, it's almost in complete realtime and there's a mindblowing amount of length to this game.