Can't believe no one has mentioned Mass Effect & Dragon Age series' ..those are the best RPGs ever created and in terms of Immersion and fun are much MUCH Better than COD series >_>
Then again really disappointed to see no one has mentioned Half Life 2! **Sigh**
FPS :
Crysis ( 1 & 2) , Bioshock, Doom 3 ( Got to be the scariest game of all time ), F.E.A.R, Half Life Series ( Best FPS game imo), Quake 3 Arena ( My personal fav! Been playing till now xD )
TPS : Max Payne 2, Mafia, MDK 2, Oni
Strategy : Starcraft 2, Warcraft 3, Dawn Of War Series. Seriously, AOE is nothing compared to Warcraft 3 or Dawn Of War 2 or Starcraft 2. Also Waiting for Diablo 3.
RPG ( My Favorite Genre ) : Chrono Trigger, Mass Effect 1 & 2, Dragon Age 1 & 2, Final Fantasy 1 - 12 ( played all of em'), Legend of Zelda ( OT, WW, TP, MM ) The Last Remnant , Secret of Mana, Lufia, Dragon quest 1 - ix.
Racing : NFS U2, NFS MW ( all releases after MW are a total flop -.- )
Others : Portal 1 & 2, SIMS 3