it's my firm belief that neither Xbox 360 nor PS3 really have enough raw pixel fillrate
(for most developers) to do 60 FPS while displaying truly next generation imagry.
both Xenos and RSX only have 8 ROPs and only ~4 Gpixel/s fillrate. 720p uses most of that up, so they're almost down to fillrates of last generation consoles once they've asended to HD resolution. I made a thread about this.
IMO both consoles should've had ~12 Gpixels/sec. nearly free 4x AA (like Xenos) and the option to goto 8x AA at moderate fillrate/bandwidth cost (less cost than with PC GPUs).
does that mean we will never see next-gen graphics at 60fps? no, not at all, but there will be few games that do it. options are, go down to 480p or cut out anti-aliasing
(cutting out AA will help PS3 more than Xbox 360).