1. The Elder Scrolls V: Skyrim
Back to form after the weirdness of Oblivion (which was good but not outstanding compared to my TES expectations). It doesn't really feel significantly "shallower" than Morrowind but somehow still manages to be quite a bit more accessible. And it strikes a great balance of production values and choice. Never really meaningfully buggy (on PC) or unneccessarily streamlined. In short: easily my favorite game this year (and I'm far from being done with it) even with company like Bastion and MK.
I was a little unsure about this game because of the amazing GB coverage and the respect I have for the devs behind it - that shit can cloud your judgement relatively fast. But Bastion has everything: very good art direction that especially shines during the trippy/ psychedelic effects in the "Who knows where" arenas and elsewhere, exceptional writing and story, presentation and - most importantly - delightful intuitive but deep gameplay!
3. Mortal Kombat
I love these games pretty much unconditionally. Even the weird, sorta bad post-MK3 part of the series. Except this time around it fucking rocks more than I could've expected and even has a well done story mode.
I wish it had a good PC version so I could add it to the collection but that's not really a valid complaint.
4. Battlefield 3
Very well worth the time and money because it's outstanding in many ways but not quite the long lasting MP "uber"-hit I hoped it would be for me.
5. Warhammer 40,000: Space Marine
Fun while it lasted and it just is such a wonderful surprise that the game turned out great.