Well I really enjoy Fallout 3 for the PS3 because it's like an adventure RPG put into a shooting game. It also has many custom features like your beginning stats, character looks, and main skills. It has a lot to explore in the game and never seems to get old. Resident evil 5 is also really good because it has the 2 player feature and it's pretty long compared to RE4. Teamwork is important.
LittleBig Planet Hands down. That game is mind blowing fun. It's the only game I know where I can live out my dream of driving a car packed with explosives that has shurikens for wheels straight into a brick wall.