Usually its difficult to go back ...once the PS1 and the N64 were out it was difficult to go back and play Megadrive/Snes ,and the same happpened with Snes and Nes ....PS1 graphics felt horrible by the late PS2/Xbox/Cube generation.
But I have to say that going back to Cube/PS2/Xbox is not as appalling as in the generations before.Yes ,the graphics are much worse than current ones but are still palatable.I think 360/PS3 graphics will keep easy on the eyes for many years to come .