Call of Duty 4. For a game that had its single player bashed for being to short, I was very happy. Most FPSs that are action driven (as opposed to games like Bioshock) seem to long to me mostly. By the end I'm just walking around like a zombie shooting at anything that moves. The story was pretty decent and I think it ended just soon enough. I still hate games that end with a
level.
The multiplayer is pretty deep, and I'm enjoying it way more then Halo.