1. Bioshock
2. Metroid Prime Trilogy
3. Bioshock Infinite
4. Mario Kart DS
5. Picross
6. Uncharted 2
7. Metal Gear Solid 4
8. Super Mario Galaxy 2
9. Zelda: Twilight Princess
10. Super Mario Galaxy

1. Super Mario Galaxy 1/2
2. Zelda: Twilight Princess
3. Halo 3
4. Oblivion
5. World of Warcraft
6. Red Dead Redemption
7. Dragon Age: Origins
8. Metroid Prime Trilogy
9. Call of Duty 4
10. Halo 3: ODST

i gamed this generation only on my PS3 and Vita so my top 10 picks will be:

1.The Last of Us

2.Heavy Rain

3.Uncharted 2

4.God of War 3

5.Resistance 2

6.Uncharted 3

7.inFamous

8.Flower

9.Trine

10.Ratchet & Clank: A Crack in Time

i've yet to play Bioshock Infinite which could potentially be in the top 10

Here is mine (based on what I have played and in no particular order)

1. Valkyria Chronicles
2. Demon's Souls
3. Mario Kart Wii
4. Super Mario Galaxy 2
5. Uncharted 2
6. Ys Seven
7. Monster Hunter Ti
8. Xenoblade Chronicles
9. Witcher 2
10. Knights in the Nightmare

I thought most of the popular third person action games were mediocre this gen. Guess that's quite different from most people. If we only count retail games my list would be. Number 2-5 are all basically even. 

1. Halo 3
2. Elder Scrolls IV: Oblivion
3. Dark Souls
4. Fallout 3
5. Elder Scrolls V: Skyrim
6. Left 4 Dead
7. Civilization V
8. The World Ends With You
9. Mass Effect 2
10. Advanced Wars: Days of Ruin

Decent list, not my top 10. But I have seen worse lists :p
AC II is the best AC, but it should be a bit lower in the top 10.

Top 10 is actually to small to list the best games of this gen.
like we're missing GoW III, Fallout 3, Killzone 2, Heavy rain, MGS4, portal 2 etc etc etc

1- Uncharted 2
2- Red Dead Redemption
3-The Last of Us
4- Metal Gear Solid 4
5- Grand Theft Auto IV
6- Uncharted 3
7- Assassin's Creed 2
8- God of War 3
9- Far Cry 3
10- Gears of War

1)The Last of Us
2) Uncharted 2
3)Uncharted 3
4) Red Dead Redemption
5) Grand Theft Auto IV
6)Mass Effect 2
7) Metal Gear Solid 4
8)Assassin's Creed 2
9) Halo 3
10) Bioshock

I haven't played all the nominees that I want to, so I won't say yet.

But here's my ideas

Confirmed to be on my list (not in any order):

Super Mario Galaxy 

Super Smash Bros Brawl

Skyrim

Infinity Blade II

Bioshock

Might end up on the list:

Bioshock

Last of Us

Portal 2

Journey

Uncharted 2

Super Scribblenauts

Assassin's Creed Brotherhood

inFamous 2

Heavy Rain

Borderlands

LittleBigPlanet 2

Limbo

Crysis

Contenders I still need to play/finish

Fallout 3

GTA IV

Red Dead Redemtion

Zelda: Skyward Sword

God of War III

Batman Arkham Asylum

Assassin's Creed Revelations

L.A. Noire

The Walking Dead (played first two episodes, looks promising)

The World Ends With You

Radiant Historia

Braid

Dragon Age Origins

I didn't like GTA 4 that much and it definitely didn't deserve to be in the top 10.
Also didn't really like Skyrim. I also think you should have Arkham City in that top 10.
And Assassin's Creed 2 was the best AC game but should not be No.1 .
Finally, you should have at least 1 Wii game in the list.