1. Assassin's Creed: Brotherhood
With a story just as messed up as AC2, great graphics, voice-acting, gameplay and multiplayer firmly cements this as my game of the year. There is just so much to do in the game: searching for collectibles like feathers or flags, "The Truth", memories within memories, amazing assassinations, commanding assassins, a story that's interesting and messed up (Sci-fi and Renaissance Italy don't belong together, but I still love it). And when you're done with all that, you go online for more stabbing, and getting the perfect kill is incredibly satisfying.
Minimalistic, yet incredibly satisfying. Limbo does everything not just well, but perfect. You will never encounter the same puzzle twice, the story is open to interpretation and the atmosphere is amazing. Limbo does what it does without fault. It is too short though.
3. Heavy Rain
I have a weakness for David Cage. The man knows how to make incredibly bleak worlds and interesting universes. I loved both Omikron and Fahrenheit for this reason. This is basically the current gen version of Fahrenheit. The amount of seemingly irrelevant stuff you can do helps make the world more believable and real. The story is where the game shines.
However, a lot of stuff was cut from the final version and that added plenty of plot holes. If Quantic Dream had just left everything they wanted in the game, I truly believe this would have been my game of the year.
4. Red Dead Redemption
Ah, finally a truly great western game. I knew I would love it the moment Rockstar announced it. The story is interesting and it has some truly great sidequests, with the Mysterious Stranger being one of the most interesting quest lines I have ever experienced. Dynamic quests make the world feel less empty, though they do start to repeat after a while. Overall a great game that does have its faults. Mexico was the absolute low point of the game, and I was delighted when I finally rode back into the US.
5. Mass Effect 2
It's... not the sequel I had hoped for. For all the good things you can say about it (graphics, gameplay, voice acting etc.), I feel the story and characters felt flat. Hire people to fight The Collectors, fight them, the end. That's basically it. Character interaction is limited to your ship. They barely have anything to say when you're on a mission, and character development is basically non-existent. There are a few interesting characters though, with Thane being my absolute favorite. The DLC's added a lot, with Lair of The Shadow Broker being absolutely excellent.
6. Battlefield: Bad Company 2
Good single player campaign, but it truly shines when you go online. Getting your butt kicked, and still win by working together with your team is incredibly satisfying.
7. Sid Meier's Civilization V
Taking over the world, one turn at a time. Developing tanks and rolling over your enemies, who have nothing but spearmen is so much fun. And when everything goes your way, Gandhi declares war on you and then proceeds to kick your butt.
8. Fallout: New Vegas
Ah, Fallout. I hate you for being buggy as hell, but love you for everything else. Even the main story is interesting this time (thanks Obsidian). This is Fallout 3 with a proper companion system. It's amazing, but do yourself a favor and play it on the PC. The mods alone makes it worth it.
9. Super Meat Boy
Brutal. That's the one word that can be used to describe SMB. You can probably complete the game without getting too frustrated, but if you want perfection, be prepared to die. Hundreds and hundreds of times. You will get to the point where you never want to touch the game ever again. And then you get it right. You time everything to perfection, and complete the level in record time. And then you love it again.
10. Alpha Protocol
Man, this game doesn't belong here. It's busted, plain and simple. But damn if I don't love it. The fact that the story can change completely depending on a seemingly irrelevant choice is what really sold me on this.