True, but the question is "BEST GRAPHIC GAME EVER", not best overall game ever. So if only graphics are considered in game and on any system since 32bit era, I say Gears of War for 360.
You are right. But since I haven't played Gears of War yet (although I could have, but couldn't be bothered to play another shooter game that looks like it plays just like other shooters), I would have to choose from the 360 games I've played: PGR3 or Kameo were the best looking ones.
But again, even though those game have great graphics PGR2 had a better career mode and Kameo is not a AAA action-adventure. Great graphics become irrelevant if the gameplay isn't great or at least good too.