1) Demon's/Dark Souls
Immensely fun and rewarding gameplay, intriguing atmosphere, amazing art direction; I love nearly everything about those games.
2) Arkham City
Like another poster said: will a Batman game ever again be this good? Simply fantastic. From the gameplay, to the stories to the way the lore is treated with all those little cameos and easter eggs. Asylum is an amazing game as well but City just took everthing I loved about this game and made it even better.
3) Deus Ex Human Revolution
Awesome story that really drew me in, great gameplay, interesting characters and the near future setting was very intriguing. Classic cyberpunk re-imagined.
4) GTA5
This game that was just amazingly fun to play. Huge, detailed world that was a joy to explore and gameplay that fixed every issue I had with GTA4(from the driving to the shooting controls). Also credit to Rockstar for giving the game cleverly written protagonists I've never seen in any other game before(for better or worse), and once again pushing the medium into different and unknown directions.
5) Max Payne 3
Another Rockstar game.
One of the best third person shooters ever made in my opinion. Gameplay is so rewarding and satisfying. Max Payne's sarcasm is often(unintentionally) hilarious and lightens up what is an otherwise pretty dark and well written storyline. Also the transition between cutscene and gameplay is flawless.
And b/c I can't stop at 5..
6) AC4: Black Flag
Best Assassins Creed game to date. The naval combat was my favorite element of AC3 so I was really glad they built the entire game around it. Also the setting was downright gorgeous and exploring it remains phenomenal. The gameplay was also improved and espescially the combat now seems to flow a bit better.
7) The Last of Us
The storyline was great but to be honest I was never really as captivated by it as many seemed to be. However the setting and atmosphere was just pitch perfect. I really enjoyed the gameplay as well. The gunplay was intentionally less precise and the melee had a raw and desperate feel to it. The game made you feel underpowered and it really heightened the experience for me.
8) Dead Space 2
Best action horror game since Resident Evil 4. Which happens to be one of my favorite games of all time so I can't think of any higher compliment.
9) Metal Gear Solid 4
Amazing 'conclusion' to the series. The gameplay is basically MGS3: Subsistence but much improved and the story had me guessing at every turn. I have been following the series since MGS1 so the attempts of this game to tie up all those loose end just left me often in awe at Kojima's creativity. Also revisiting Shadow Moses was just...pure nostalgia.
9.9) Mass Effect 2
First ME game I played and still my favorite. Excellent characterization and the Reaper threat really gave the game an ominous feel. The ambiguity about the nature of this threat is what really drew me in, more so than the actual story itself. Gameplay was also excellent.
10) Dishonered
I loved the authenticity in the setting of this game, it felt like a place that could have actually existed. The gameplay and story were also excellent.
Honorable mentions: Sonic Generations, Spec Ops The Line, Transformers Fall of Cybertron, Fallout 3/NV, Skyrim, Oblivion, 3D Dot Game Heroes, Vanquish, Tomb Raider, Silent Hill Downpour, Hitman Absolution, Bioshock, Bioshock Infinite..and probably some I forgot in one of the best console generations.
I would mention the HD collections of Ico/SOTC and MGS as well for being truly excellent.