Exclusive wise, I've been having a lot of fun with Demon's Souls this last week. Other than that,
For FPS games, Resistance 1 and 2 and Killzone 2 are good. The up coming MAG is addicting, but it can get chaotic pretty fast.
RPG Wise, Demon's Souls and Folklore are both good action RPGs, Valkyria Chronicles is a solid SRPG, exclusive traditional RPGs are hard to come by outside of japan, but 2010 has some promise.
Uncharted 1 and 2 are both good fun. A solid mix of third person shooter and platformer.
Other random fun titles. Katamari Forever (if you like the franchise) Ratchet and Clank Future (and of the three titles) God of War Collection comes out on tuesday if that's your thing. Heavenly Sword is repetitive, but fun as well.