AH, so we've moved to 2012. Let's see...
First, the disappointing big ones :
Mass Effect III. Let's be clear : this is for me the game which destroyed and despoiled the ME serie. I have now a hard time playing the previous ones (despite them being among my top favourite games) because I know they will end up in this garbage.
Dialogues are good and characters are excellent - the banter is sometimes truly glorious. But the utterly moronic plot and complete waste of the entire setting is just disgusting. It's dumb, it's throwing away the rather realistic settings, it's crapping all over the rest of the serie and making you doing the same thing again, but worse, and I'm not even including the famous ending debacle, I'm talking about the entire rest of the game and story. It's not just, like Skyrim, about being overrated (though it still is), it's even worse, it's about adding negative value to the entire serie. I utterly despise this game because of that, and even more considering the amount of good material included in it but completely wasted (especially the "renegade" choices, which in the end feel like the only giving a powerful narrative, but which are all subpar by design). So no, it's certainly not going to be on my "best" list. Eugh.
Diablo III : a farce. Let's end it at that.
Now, the actual good ones :
Kingdom of Amalur was a commercial failure, but more because of the high cost than the lack of sales. It also didn't really reach as much as it should have. Nevertheless, it's one of the very best action-RPG I know, with a pretty good fighting system (which I find infinitely superior to all the Diablo clones) and enough dialogues, choices and freedom to actually deserves the "RPG" part. It's also a HUGE game (it sometimes really feels like a solo MMO) which have tons of content, and a very interesting lore. All in all, I'd say it's a very underestimated game, whose main flaw is that it becomes far too easy after awhile. Still one of the very best game of the year, and one allowing you to feel like a BADASS.
Crusader Kings II is a rather in-depth niche game from Paradox (medieval dynastic simulator, that's certainly something you don't see elsewhere). Very very unique, with all the good things (complex, gripping, accurate) from Paradox, but also many of the bad (a bit all over the place, dubious design decision, cascade of DLC everywhere). Very good, but TBH it, like EU4, suffers too much of the Paradox policies about said DLC after awhile, which tends to trip the game with constant unrequited changes.
Legend of Grimrock is a symbol of the then-newfound indie movement and low-budget modern games. It's pretty good, but honestly it's more impressive as said symbol than as a game. Nice moment, immersive and an interesting modern take on a (very) old-school design, but while very pleasant I don't think it can claim any kind of "game of the year" title.
Samely, FTL is good, very good, but I'd see it more as a gripping time-killer than a "game of the year".
Borderlands II : following on the same comical-gore-refuge in audacity FPS formula of its predecessor, but with a much improved gameplay (less meatshield, more aiming) and an absolutely dreadful interface which should deserve death penalty, this game is overall even far better than the first one. More content, longer, much more memorable characters and story, funny, full of action. Not deep, but great fun.
Dishonored : a fantastic artistic direction combined with a (very) predictable but good story that proves the power of the narration doesn't need to surprise the player, and one of the most empowering set of ability in a game ever (dat Blink). One of the few games (with Deus Ex) with good enough level and game design to actually really allow you to play how you want, and a superb ambiance immersing you into its world. Too bad it's so short.
Assassin Creed III : I'm very ambivalent on this game. The story is pretty good, with a lot of thought and an INSANE amount of historical research put into it. The game is huge, the characters are quite deep and there is always something more than what it looks like.
But the setting is pretty poor for the gameplay (grid-like US cities made of square buildings are just boring and very limited when it comes to parkour compared to AC2's convoluted architecture), most of the content (the side-quests, the ship, the colonization) is so completely optionnal as to pointless (you don't need anything from it, and you already have more than you need from just doing the MQ), and the main character, despite being well written and being, in fact, more complex than Ezio and very self-consistent, is just boring and annoying. That's a bit of a waste when you'd actually prefer to play the antagonist side - it makes for an interesting grey vs grey world, and a surprising "you might be wrong" narrative, but in the end it just doesn't give you incentive to play as the hero you are given.
So, among these, I'd say my favourites are fighting a three-ways battle between Kingdom of Amalur : Reckoning, Borderlands II and Dishonored.
I'll probably nominate Dishonored in the end.