Valkyria Chronicles is all you need as far as exclusives go...
LBP, Uncharted, HS, MotorStorm 2, GT5, Dark Kingdom, and Folklore are all fine PS3 exclusives aswell.
Prince of Persia, Assassins Creed 1, Armored Core: For Answer, SoulCalibur IV, and Mirrors Edge are great games to, there not exclusive but there great games none-the-less.