Look, they both have awsome graphics. Yesterday when I was doin' my training at the BestBuy, I saw this xbox360 setup hooked up to a kickass Samsung LCD HDTV. Some guys were playing (what looked like burnout?) and it looked f'in amazing. I was actually pretty surprised because I haven't really witnessed the xbox 360 in person, and on that sexy LCD, it was not bad, not bad at all.
Also just so you do know, the xbox 360 is easier (or should be) to develop for since it does use the MS DirectX language (a more familiar platform). It takes time (as some have already stated) for developers to get familiar with the programming language and ect on a system like the PS3.
Anyways. Both systems are great, and they both should offer their own unique experiances.