What are some of the better PSP games?

okay so I've had a PSP for a while now but I don't have that many games for it. I was just wondering what are peoples favorite PSP games available right now? Im looking to get a new game or a couple so please give me some suggestions.

Well I only have 3 games (Daxter, Medal of Honor: Heroes 2, Star Wars Battlefront: Renegade Squadron)

and so far Daxter is my favorite, but thats mainly becuase Medal of Honor cramps my right thumb (I broke it last year ^^)