I was mostly a pc gamer this year, and I think there were a lot of great games released this year. Of the ones I could play, I found these to be the most memorable.
Magicka
Bastion
The Elder Scrolls V: Skyrim
Terraria
Deus Ex: Human Revolution
Cave Story+ (Cave Story's been around since 2004-ish, but was given some new graphics/music and re-released on Steam this year.)
I want to say Trine 2, since the first Trine was magical, but I'm holding off on playing it until I find a co-op partner.
Not sure if I should include Minecraft since it's been around forever but was officially "released" this year.