The PS3 has more potential, however, for the moment, it's exactly the same.
But if you need help deciding, you already know my [Only registered and activated users can see links. ].
However, I'll give you an example of the "best" exclusive graphics on the PS3 and 360.
PS3:
Uncharted: Drake's Fortune
This game blows any other console game out of the water. Sure, it's about 7 months old, but it's still visually breathtaking. If you roll around in the dirt, your shirt and pants get dirty wherever the dirt came into contact with you. If you jump into water, you get wet where the water touched you. There are over 65,000 character animations, which would be the most for any single character in one game.
XBOX360:
Gears of War
Same gaming concept behind both games. If you'd ask me which game is better, I'd point to Uncharted because it feels like a more colorful, refined version of Gears of War. This game's graphics are still the best ever achieved on the X360, even though it came out years ago.
Though, if you want me to be honest, PC has the best graphics capability over all other systems.
I have a Playstation 3 and the graphics are amazing. I don't even bother trying to purchase a 360 because I know all the people who say it's better, just can't afford such an amazing console!