Its very hard to say and it depends what kind games you like. My favorite racing game for ps3 is Mod Nation Racers and I can't say my favorite action game is so here is a list:
God of War 3
Uncharted 2
Cal of duty black ops
Bioshock 2
Assassins Creed 2 (Assassins Creed brother hood is probebly good to but I havent played it)
and others!!
The best game is out of Fifa 10,COD MW2, Assassin's Creed II and DJ Hero (by the way I'm talkin' about 2010 games)
Ok, all of those games are good (But fifa which sucks!) but the BEST game is either bioshock 2, assassins creed 2, and God of War 3!
NO it was aclaimed the BEST PS3 game!
the best ps3 game is What ever you think
Infamous 2
Ps3 or psp are the best.
In my opinion Dead Island is the best, it depends on what you think of the game.
uncharted 2
Demon's Souls
Killzone 3
fifa 11
FALLOUT 3
battlefield:bad company 2 is the best game of 2010 and the best multiplayer game
The best adventure game would ultimately have to be Little Big Planet.