Currently...BATTLEFIELD 3.
I found myself sometimes laughing hysterically when I shoot other players. The satisfaction of slaying a fellow human being in their futile afford to turn the tide of battle. HAHAHAHAHAHA!
Have the best memories with the Age of Empires series (including Age of Mythology).
For Multiplayer it's Warcraft III: The Frozen Throne (with DotA, XHero Siege, Enfo's etc.).
And last but not least: The Mass Effect series ... just sad that the series ended with ME3.
Mine is Civilization 3: Conquest/ Complete as well, Complete because of all the extra scenarios that I enjoyed when I didn't use internet for a long time. Conquest for the well... Conquest. I also enjoy Age of Empires II as well both games led to my high fascination with history.
Hmm, hard to really say as I really hate playing games on my PC~
Past: Diablo II till upgrading Final Fantasy XI from PS2 to PC~
Present: Melty Blood Actress Again Current Code or any of the Type-Moon visual novels~
Future: Final Fantasy XIV A Relm Reborn (Maybe?) and both new Mahou Tsukai no Yoru visual novels that are coming out~
I really enjoyed the elder scrolls saga, but i think the best pc game is Monkey Island. I played that thing for so many days! The Assassin's Creed saga was goid too!
For me it's Total War Shogun. Still have that game installed in all of my PCs through the years. Spent countless hours with it when I first found it and still have give it a go now and then.
I have Total War Shogun2 too. It's prettier, has a much more comprehensive gameplay and a lot of stuff for you to do. Overall, TWS2 is a better game than TWS but for some strange reason I prefer the first, decade old Shogun as my favourite.
Crysis 1
The first game which was challenging for me. Run around in cloak and you drain energy instantly. Play call of duty style and the koreans flank you, frag you, call reinforcements. Plus it had quality graphics, for a game of its time. Also them enemies had tough armor.