FEAR 2 isn't revolutionary, but I loved playing through the single player campaign for the level design and action. Plus the weapons were rather fun, though you only got a few shots with the BFG (at least that's basically what it is for those of you who played Doom 3.)
SPOILER ALERT: DO NOT READ IF YOU HAVEN'T FINISHED THE GAME!
How did your character knock up Alma at the end, lol? She was totally pregnant, and then the game ended!