I don't really have one favorite video game, I just have some games that I loved lol
Borderlands (I just love this new role playing shooter genre lol, also I'm playing borderlands 2 and it looks awesome)
Bioshock 1 and 2 (Nice graphics and really awesome story)
Heavy Rain (just epic from every angle)
God of War series (I mean, have you seen Kratos already? How could he not be on this list?)
Call of duty 4 (Great story, nice graphics and awesome multiplayer)
Dota 2 (most balanced competitive moba game, so pretty much it, also nice graphics)
osu! (no explanation needed)