1. Dark Souls
This and Demon's Souls are still some the best action-RPGs ever made thanks to From's attention to incredible level design, atmosphere and of course the intensity of the gameplay. Aspects of Dark Souls still remain better presented in Demon's, but that did not stop me from playing the game for over 200 hours and feeling satisfied every minute.
2. Batman: Arkham City
A improvement on Asylum in every way. Combat is relatively the same, though you can feel some tweaks to things that may have annoyed you in Asylum. The villians are portrayed perfectly here through their voice actors (though Batman's is still as stale as leftover motzah)
3. The Witcher 2: Assassins of Kings
A true technical powerhouse, The Witcher 2 is one of the best RPGs I've played in a while. CDProjeckt obviously knew what we would want from them, and they delivered. Unfortunately the game clocks into about 20 hours, which is disappointing from the Witcher 1's 35+ hours of sidequests.
4. Deus Ex: Human Revolution
An RPG where you actually get to play the way you want to play things. Wow what a concept, right? Too bad it's a bit too short and the graphics are a bit muddy.
5. The Elder Scrolls V: Skyrim
With a huge and open world, Skyrim seems to offer everything, but thanks to the fact that there has been no creation kit released during these 2 months, the Bethesda-made dungeons are really starting to feel stale
6. Dota 2
Look I know it's not "out" yet, but I've played 150+ hours and it was the only good competitive multiplayer game this year so there you go
7. Dead Space 2
One of the best ways to start a new year ever
8. Portal 2
A wonderfully crafted game, but unfortunately loses replayability.
9. Total War: Shogun 2
This game was definately not a shameful display
10. L.A. Noire
A fun and interesting game, too bad the gameplay gets rather shallow and the graphics are particularly ugly on PC (compared to other PC games)