P4G and Gravity Rush as you already said.
LittleBigPanet is an amazing game (imo) and i'd recomend Soul Sacrifice but it's not a game for everyone and it take some getting used to (there's an extensive demo for it so trying that woun't hurt).
I also quite liked Ragnarock Odyssey but it you decide to get it wait for Ragnarock Odyssey Ace its the same game with aditional content and should repopulate servers, the eu ones are almost dead but i've heard the us ones are good and since the game is way better playing with people that's sort of important.
If you like braintraining games Smart Ass... is pretty good and if been pouring a lot of time into it recently (trying to get every game to the genious level - seems fucking impossible), it's also pretty ceap on psn now.
And then of course there is Uncharted, it's like.... Uncharted.
As for psn games i'd say Guacamelee is the best sidescroller i've (ever) played, the game it absolutely amazing.
If you like profesor layton kind of games i'd recommend Jacob Jones and the big foot Adventures. It's a nice puzzle games with charming characters and story and it's an amazing price for what you get... waiting for episode 2 sort of sucks though.
And last but not least try Frobisher Says, it's some crazy game and imo a ton of fun and it's free so no excuse not to try it.
Some upcomming games to look out for is YS Celceta (king of the jrpg's), tearaway and feedom wars seem to look promising and the beta impressions of killzone are verry posotive. Also i'm quite looking forward to invizimals (but that might be just me).
