I'd say CoD4. As awesome as that game is, it also inspired a lot of devs to go lazy ( *cough Capcom *cough*) and make their franchise CoD clones.. This is the love-hate relationship I have with CoD4.. It's a double edged sword.. It's very complicated. :(

It would have to be Uncharted 2 for me easily. The first game that my whole family wanted to sit down and watch me play through. Entertaining and thrilling throughout the whole single player story. Add on an excellent multiplayer mode that it didn't even need to have to be considered a great game and you have the most complete package from the previous generation.

COD4.
Its what made me upgrade to the PS3 from the PS2 and I played it constantly for almost 2 years.
It also got me back into online gaming after I spent a long time away from it because of PC.
I eventually did get this for PC too and it was very fun when I eventually found a server without hackers and big ego's and the maps were not over or undercrowded (yeah looking for a good PC server is like finding a habitable exoplanet, its hard but pays off when you do)

There are better games I played but I think COD4 is definately the most influential.

Whilst Super Mario Galaxy is easily my fav game on that list I don't see how it was very influential.

Cod4 (led to the "FPS generation") or Uncharted 2 (led to many games of its type...Tomb Raider being one of the latest clearly influenced by it)

Just because you may not be a fan of COD, it doesn't negate what it has done for the industry, good or bad. I haven't bought a COD since Black ops, and i don't think i will ever buy another one, but it would be stupid to ignore what COD4 did to the industry. 

^This, it brought mainstream attention to the new-gen, but kinda made the gen stagnant in the process. 

yeah, i had a feeling alot of people would misinterpret the title. My favorite game of the gen would have to be TLOU, but i don't think that it will be as influential as either COD 4, or Wii Sports, there is a difference between favorite and influential, some people can't grasp that fact. 

It's a tie between COD 4 and Assassin's Creed. They had an influence on just about every other game last gen.

Skyrim.

For most influential games of the generation, I would say Wii Sports and CoD: Modern Warfare. Wii Sports spawned the motion gaming craze, and forced Sony and Microsoft into creating their own motion gaming controllers. Modern Warfare spawned a bunch of copycat FPS.

I don't think either are the best games of the generation, but that is a different discussion.