Honestly, I think there is already an answer. Warhawk was supposed to destroy in the graphics department with its photorealistic "in-game" screens a while back (100% photohop, btw- 0 game). Now, it looks worse than Crimson Skies in pretty much every measurable aspect.
GT:HD? Xbox (1) could definately run that if Xbox were enabled for 1080p. And as I've said, Xbox would probably also add anti-aliasing to minimize jaggies.
There are some exceptions, such as the new Sonic game, which people said basically looked the same on both systems, barring personal taste for changes on the two versions. But I'm pretty sure there is no case of (real, swear-to-God, on-hardware and actually running) gameplay footage on the PS3 yet topping anything Xbox 360 is already doing (like Gears of War).
The problem is trying to get Sony fans to come down to Earth and talk about games that are actually running on real hardware. See also: Assassin's Creed may be coming to or already on 360, the Gran Turismo:HD demo wasn't running on real hardware and some execs got embarassed because they couldn't turn the volume up on an essentially non-functioning demo station even though it still looked like crap... etc, etc, etc.
Graphics don't make the game, but they can embarass a company that's expecting you to pay $200 more for them.