Didn't meant to Kudo lol.
Welcome to the PS community!
Anyway, definitely check the Uncharted series. They're all great games. Of course if you have a PS you got to have a GT game too. Be sure to look into LittleBigPlanet. I'm not sure how good LBP Karting is but LBP 2 is a great game for sure. Then there's Heavy Rain of course. And the recently released Ni No Kuni Wrath of the White Witch, which I haven't personally played yet (EU), but all agree that it's an amazing game!
ETA: Also check God of War III
I'd personally say..
Heavy Rain - Undoubtably the best graphical experienece and story driven game of this generation. Extremely underrated game, maybe it's because it plays out more like an interactive movie, but it's absolutely breathtakingly awesome with multiple endings to explore, over 14 I think I remember it as. - Single Player
Yakuza 3/4 - Both are Japanese with English subtitles, excellent games with loads of side quests, in game arcades, and loads of other stuff. The only creative franchise Sega have left. - Single Player
Uncharted.. All of them are worth getting even though 2 is by far the best one of the lot. - 2 and 3 have multiplayer
Beyond: Two Souls will be out either this year or next year, that will also be fantastic. - Probably single player
Thats it as far as exclusives go from my view unfortunately.... There really isn't a lot worth playing on the exclusive side of Multiplayer for the PS3. All the good stuff is on the 360 for multiplayer exclusivity, unless you intend to buy games on the PS3 that are available for both consoles then I could throw a much bigger list at you. 
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