TOP 5 THIS GEN:
1) MGS4
2) BioShock
3) Gears of War
4) Oblivion
5) Tools of Destruction
TOP 5 OF ALL TIME:
1) MGS4
2) God of War
3) BioShock
4) Gears of War
5) God of War 2
I just have to mention, I feel sorry for it:
6) Ratchet and Clank: Up Your Arsenal.
Note that the lack of games not on Sony consoles is because other than the Gameboy Colour I have never owned a non-Sony console. I have, however, played Gears of War many times and love it.