One game?! No I have to do a list, here goes. Tomb Raider. Max Payne. Maybe a hundred times I played it. Resident Evil. Hitman. All the Legacy of Kain series. Blood Rayne. All the Sherlock Holmes games specially Vs Jack the ripper. Seek and find games. Vampire the mascarade 2. Devil may cry 4. Silent colline 2,3. Amnesia. Penumbra. Grand theft auto. Mortal Kombat. Darkness within. American Mcgee's Alice. Need for speed. ONI <3. Dead rising 2. Batman arkham asylum. Wolfenstein. Medal of honor.
I'd have to say the first Halo back in '01, I mean I'd be up playing that game for hours on end. Just an awesome original story line and all... But then again the first Splinter Cell game was amazing too, I beat that game so many times, and couldn't stop replaying it. I had every security camera, and guard's position memorized par heart. Then I also liked GTA San Andreas too, cause my bro and I would play that game non-stop, so IDK... It's hard for me to pick just one, but It'd have to be one of those three, and if toi ever get the chance, watch Scarface and then play any GTA... If you're as weird as me you'll catch yourself trying to do Tony Montana impressions while playing XD... *shooting someone* you'll be like "F*ck toi Main! I'm Tony Montana! toi f*cking with me! toi f*cking wit de best!" LOL!!!