looks less realistic on the PS3, but the blacks on the PSĀ£ look better. Probably the different disc types play a large role in the general quality you can get as Blu Ray gives you better blacks and DVD more detail can be stored on the disc.
PC is by far the best looking, Xbox is next as all the textures have more details than the PS3 textures. Overall there really no major differences and are all very playable so this comparison is a bit pointless
wooly_mamoth's comments