@ Audiomatic
That's pretty obvious isn't it? Top audio and graphics do however add to the experience (or are you playing on a mono black & white telly?). And the technical differences between the 360 and PS3 do not only relate to graphics and audio, also the amount of stuff you can do, how complex you can make a world to be, etc.
One thing to note, those games which have the best gameplay almost always get some special treatment from the developing company in terms of graphics as well. For example Super Mario Galaxy, Killzone 2, Gears of War, Uncharted, etc.