I never got a chance to play Patapon 2, so I cannot comment on that.
For shooters I did get to play Syphon Filter: Combat Ops and Resistance: Retribution. My opinion on them is that they are very, very fun, but you should probably try before you buy if you can. It's sorta annoying to use the face buttons to control the camera angle. From what I understand, Combat Ops had a pretty good online MP for it.
I dunno how you feel about custom firmware, but emulators make things a bit more interesting. But, that'll keep you from playing the newest games. (Not that anything good is coming out anymore.)
I enjoyed Burnout: Paradise, Dynasty Warriors Vol. 2, Tales of the World, God of War, Dungeon Maker, Valhalla Knights, Obsure: The Aftermath, etc. Most are RPGs, and thats most of what I play.