Fallout 3- Maybe the best game this gen. I remember seeing a demo of the game but not too much. My mind was blown the first time playing it. I've probably played it over 500 hours across all my playthroughs.

God of War 3- Definitely delivered.

Mass Effect 2- I loved the first game but this is 10x better.

Resistance Fall of Man- Probably my funnest experience with MP besides Black Ops 1.

Arkham City- Far better than Asylum

Oblivion- My step brother tried getting me to get this forever and eventually he bought it for me. Loved it.

I can't believe some of you are mentioning Uncharted 3. What a huge step down for Among Thieves. The ended was terrible. I don't understand how it hasn't had backlash. Sure it doesn't matter as much as in mass effect but the ending is still very important to such a huge trilogy. 

It's gotta be Red Dead Redemption

Uncharted 2
Modern Warfare 2
Skyrim
Pokemon Soul Silver
New Super Mario Bros Wii

After all this time I'm gonna have to eat crow and say Mario Kart 7. Gameplay is beyond excellent, and the only thing that is unbalanced is the dreadful Blue Shell.

Other than that, Halo 4 pretty much nailed it.

Skyward Sword, Smash Bros Brawl, Kirby's Epic Yarn, Super Mario Galaxy.

Bioshock - expectations exceeded

killzone 2 multiplayer -  not a huge multiplayer gamer the only ones i played and liked enough to keep coming back where  halo 3 and rainbow 6 vegas so i didn't think  i would like it  and I loved it for some reason it just clicked with me .

Also resistance 2 online co-op exceeded my expectations and is the only thing I missed from resistance 2 in resistance 3.

Galaxy 1 and 2, Zelda SS

Uncharted 2
Dark Souls

weird I think I just have natural disposition towards games with 3 in the title because AC3 and U3 are my favorite games in their respective franchises and yet no one seems to like them better than the 2s and many seem to think they dissapointed.

Deus Ex: Human Revolution.