Obviously? Lol, I bet you're one of them guys that bought a 360 and has a rack for three games: COD 4, 5 and 6 and then states that Modern Warfare is the best game ever.
Mine favourite would have to be Unreal Tournament 99 or 2004. Fast-paced shooters with a really nice and mature online community. Also a large modding community which always makes online play a bit more interesting. Unreal Tournament 2008 was also good, but really failed to live up to my expectations sadly.
Played so many that it was hard to pick one out of the bunch, but I'll say it would have to be GTA San Andreas. I loved the gameplay, the story and the characters (Kent and Macker). Loved it so much that after finishing it on the Ps2 I got the pc version and did it again (btw it sucked playing on a laptop, had to remap a lot of the controls for the aircraft) And Toreno and his flight school missions need to die!
