Super Mario Galaxy. Innovation, content, graphics, music, controls and gameplay. Video game immersion and escapism at its best.

Xenoblade Chronicles would be my runner-up, one of the greatest RPG's ever made. Mass Effect 1&2 would be in the mix as well. Call of Duty, NSMB, Brain Age and Wii Sports should also be in the discussion for the impact they had on gaming as a whole.

The last of us. It was the definitive game of this gen. Brutal, beautiful, masterpiece.

God of War 3: it looks great, plays amazingly well and is challenging enough that I come back once in a while to re-do it!

This is also the game that made me love my PS3 for games.

I come to think of it, I mostly played Sony published games on the PS3 for the whole generation (I played 3rd party games on PC).

Super Mario Galaxy (1 or 2 doesn't matter). The game was just magical, it's so rare to have a game come out that really just wows you but Galaxy did it. The gameplay, music and graphics were all stellar, I don't know if we'll ever get another Mario game this good again.

Honourable mentions go to Metal Gear Solid IV and Dark Souls.

Super Smash Bros. Brawl, my cousin comes and visits my brother and I very frequently and SSBB is the only game that has kept us entertained for over two years, the characters are amazing, every time i get bored of a character the next one that i try proves to me that you can't get bored of SSB, Galaxy 2 was fantastic but still well behind SSBB, as i said the chaotic fun of three or four players dying and shouting in the same room, the amazing arenas and the amount of time i spent playing it (over 1000 hours) are the reasons why it is the best game this gen

     Mario Galaxy..  The graphics are gorgeous, it has one of the best soundtracks ever in a video game and  also one  of the best level design ever in a 3D platformer. It's slightly linear, but that's a small thing.

Pokemon Heart Gold / Soul Silver.

Although if we aren't talking about remakes, according to my top 50 games of all time list it's Final Fantasy XIII, although I'm not 100% sure about that. Call of Duty 4 and Tales of Vesperia could take the #1 spot.

I'm divided between Gears of War 3, Infamous 2, Red Dead Redemption and Smash Bros Brawl. All awesome games, and all have something different and unique.

Can't choose one.

Red Dead Redemption

It was simply just a lot of fun. Loved the setting, loved the characters, loved the story. I platinumed it too, so clearly I liked it

A close second is black ops 1.  I played the shit out of the MP

If it's a game first released on this gen, I'll go Metroid Prime 3. An excellent ending to a trilogy that combined Metroid's signature exploration with a more focused story. The inclusion of the moveable gunship was a great improvement and one that I hope sticks with the franchise going down the road, and Hypermode worked wonderfully as the biggest new "gimmick." Hypermode allowed for another level of strategy and planning with choosing to either deal damage or conserve health, and the invincibility surrounding Hypermode made the player's timing of it all the more crucial (especially when enemies gain the ability to knock the player out of Hypermode).

Outside of that, it's pretty much all great as well. The Wii remote controls work wonderfully, the action (and particularly the boss battles) are all excellently designed, the music is top notch, and the graphics still look better then some late gen 360 and PS3 titles. The only big complaint I have is that the game never explained that "Normal" difficulty for Corruption was toned down significantly from other normals in the past, and players should've started on Veteran if they had any sort of experience with Metroid.