Resistance 2 for me, followed by Killzone 2 and GTA IV. Motorstorm 2 and White Knight Story looks very interesting as well.
Sales wise I think MGS4 probably takes the crown on the PS3 this year. Lots of media hype for LittleBigPlanet as well, but has Ratchet & Clank future paved its way to drag in enough platformer fans or will LittleBigPlanet/Home and probably a pricedrop pave the way for Jak & Daxter on the PS3?
The next game I am probably going to buy is WipeOut HD from the PSN store.