Team Fortress 2
I probably have posted about this before but this is the only game that I find myself constantly playing. I love fps games, and this one is just the right amount of fun and humor to allow for a constantly enjoyable experience. My class of choice is probably the scout only because of the speed and the fact that I love throwing my guillotine around and getting some extra damage. Steam says i've ranked in 154 hours of gameplay, which is the most gameplay out of all my games.