1. Dark Souls
I don't think I've ever played a game that feels so fresh while being such an established concept. It's a hack and slash action RPG set in a medieval world with dragons and zombies, it shouldn't feel as unique as it does. Dark Souls feels so different because it simultaneously seems incredibly well designed, but simultaneously opaque and legitimately confusing in a way that makes it seem endless and limitless.
You could say Demon's Souls did it first, but the way the world in Dark Souls is structured has become a primary factor in why I enjoy these games. Having everything strung together directly makes the world seem huge and labyrinthine in a way no game has before for me. I've never felt a sense of wonder from a game the way making it through the dank and miserable Blighttown into the beautiful, heavenly Anor Londo. It's moments like these that make this one of my favorite games ever.
In a generation defined by mediocre, short experiences mostly playing like either Gears of War or Modern Warfare, this was exactly the breath of fresh air no one knew they were looking for.
2. Mass Effect 2
3. Rock Band 2
Rock Band (and Guitar Hero) is a game that was so fundamental to my life for so many years through high school and college that I have a hard time considering it as just a video game.
I played it so regularly for so long, it became another thing entirely for me, something I could actually call a pastime, something I used to burn off steam and relax with every night, something I practiced and competed in tournaments in (and won humblebrag humblebrag). For around the first three years I owned it, my Xbox was basically a Rock Band/Guitar Hero machine that also played some other games occasionally I guess.
It's easily the series I've played the most, out of anything ever, and I see Rock Band 2 as the peak of my enjoyment with the series. Yes, Rock Band 3 added a whole hell of a lot more stuff, but most of it kinda bounced off of me for whatever reason. It turns out I didn't want cymbals for my drums or second kick pedals or keytars or three part harmonies, and it's telling that they dropped most of that stuff in 4.
Rock Band 2 hit just the right balance, fixing UI issues and improving on the playability and note charts of the first game just enough to be endlessly enjoyable. Not to mention about 300% more passion for the music than erm, some other developers out there.
4. The Last of Us
5. Uncharted 2: Among Thieves
6. Metal Gear Solid 4: Guns of the Patriots
7. Super Meat Boy
Why is it that the games that most deserve a sequel never get them? If this team had been given the budget to build out a more satisfying, varied campaign it would have been a game I'd never shut up about, but as it was it felt a little shallow.
Even with its shortcomings, this game still wins the award for game I think the most about when it comes to fun and legitimate creativity in shooting mechanics.
If you need more convincing, here's a fairly common scenario in Vanquish:
You're getting ripped up out in the open, so you dodge quickly into cover.
Hit dedicated smoke cigarette button.
Toss lit cigarette over cover, distracting enemies.
Go into slow motion, slide out of cover on your rocket powered knees, headshotting each enemy as you go.
Look forward, see big robot with minigun shooting at you ahead.
Dodge through bullets and drop kick him in the face.
Robot falls over and explodes like a Power Rangers monster.
Again, this is not a cutscene, this is not a boss fight, this is a common scenario in this game.
9. Batman: Arkham Asylum
10. The Elder Scrolls V: Skyrim