Interesting topic and I love lists. So I'll catagorize mine. Favorite- Borderlands2. Most fun I've had online- Black Ops1. Most awe inspiring- Battlefield3. Best looking game for it's time- Red Dead Redemption. Best new gen- Red Dead 2.

My top 10:

10. God of War (PS4)
9. The Last of Us: Remastered
8. Portal 2
7. Diablo
6. Bioshock
5. World of Warcraft (Wrath of the Lich King era)
4. Metroid Prime
3. Half-life 2
2. Final Fantasy VII
1. Halo