Definitely LittleBigPlanet.. umm.. other than that I can't really think of anything that hasn't been said... as for PSN games, Super Stardust HD is a good arcade pickup and play shooter.. all the Pixeljunk games (except pixeljunk racers) are really good. flower is good, echochrome is good if you like that kind of thing... also, its not PSN but you might like modnation racers if you're a fan of mariokart...
Also I know you said you didn't want an FPS but I still highly recommend MAG because it is unlike any other FPS out there that I know of in that its huge games (64-256 players in a match) force you to play as a team if you want to have a prayer of winning and thus makes it a much more enjoyable experience then say COD imho. It is online only just fyi though...
Not trying to be a fanboy. Of course, it's hard when you own the best console eve... dang it
