1. Final Fantasy XIII
2. Tales of Vesperia
3. Call of Duty 4: Modern Warfare
4. Pokemon HeartGold / SoulSilver
5. Crisis Core: Final Fantasy VII
6. Fallout 3
7. Assassin's Creed II
8. Grand Theft Auto V
9. The Last of Us
10. Super Mario Galaxy

Persona 3 Portable will probably be added to the top half of the list in the near future. I may have manipulated the list to make sure only one game from a series was on there.

1. Dark Souls
2. The Last of Us
3. Metal Gear Solid 4: Guns of the Patriots
4. Demon's Souls
5. Portal 2
6. God of War III
7. Dragon's Dogma
8. Uncharted 3
9. Final Fantasy XIII-2
10. Journey

11. Heavy Rain

12. Kingdom Hearts : Birth by Sleep

13. Infamous 2

14. Assassin's Creed II

15. Final Fantasy XIII

Dark Souls II and Beyond Two Souls would probably make it to the list when I play them.

I vote for these games:

MGS4
Xenoblade
GTA5
Mass Effect 3
Halo 4
Mario Galaxy 1 & 2
Bioshock Infinite
Smash Bros.
Golden Sun Dark Dawn
The World Ends with You
Mario Kart Wii

1. Red Dead Redemption
2. BioShock
3. Batman: Arkham City
4. Mass Effect 2
5. Super Mario Galaxy 2
6. Skyrim
7. Xenoblade
8. Gears of War 2
9. Halo: Reach
10. Uncharted 3

1. Xenoblade Chronicles
2. Pokémon Mystery Dungeon - Explorers of Sky
3. Mario & Luigi: Bowser's Inside Story
4. Twilight Princess
5. Super Mario Galaxy 2
6. Skyward Sword
7. Ace Attorney - Trials & Tribulations
8. Asura's Wrath
9. Professor Layton and the Lost Future
10. Ace Attorney: Apollo Justice

Honorable mentions -
11. Pokémon Platinum
12. Professor Layton and the Curious Village
13. Spirit Tracks
14. Super Smash Bros. Brawl
15. Call of Duty: Modern Warfare 2

You can come change it if you want but I decided to do it now because there isnt really anything too noteworthy left that isnt also on next generation consoles.

Even though GT is big racing games have never done good in this competition.

I also vote for:

Final Fantasy Crystal Chronicles: The Crystal Bearers

Kingdom Hearts Birth by Sleep

Final Fantasy Crisis Core

The Last Story

Pandora's Tower

I hope I didn't forget anything else I actually liked during this crappy past Gen (7th Gen).
I can't believe that I of all people forgot about any JRPG's LOL.

Also:

Pokemon Black & White 1 & 2

Batman Arkham City (and its 3D ready, LOL)

1. Demon Souls
2. Elder Scroll V: Skyrim
3. Fallout New Vegas
4. Fallout 3
5. Dark Souls
6. Final Fantasy XIII-2
7. The Last of Us
8. Elder Scrolls IV: Oblivion
9. Borderlands 2
10. Bioshock Infinite

11. Final Fantasy XIII
12. Star Ocean: The Last Hope
13. Tales of Graces f
14. Tales of Xillia
15. Valkyria Chronicles

This is REALLY hard to narrow down

1. The Legend of Zelda: Twilight Princess (GCN/Wii)
2. Portal 2 (PS3)
3. Last of Us (PS3)
4. Dragon Age: Origins (PC)
5. Tales of Xillia (PS3)
6. Sly Cooper 4: Thieves Among Time (PS3)
7. Ni No Kuni: Wrath of the White Witch (PS3)
8. Uncharted 2 (PS3)
9. Ratchet and Clank Future: A Crack in Time (PS3)
10. Little Big Planet 2 (PS3)

Honorable Mentions

Super Mario Galaxy (Wii)
Batman Ark Asylum (PS3)
Journey (PS3)
Heavy Rain (PS3)
Final Fantasy XIII (PS3)

I could easily have a list of 30 games and struggle with cutting many of them. Of those here I could also move some around no issue. Very very challenging to list.