Seriously, both system would have the same graphics when it comes to games that they both have because the developer would only need to port the game to the other system and their job's done. They're pretty much the same, it only comes down to preference: Do you want Blu-Ray or HD-DVD, motion sensor or vibration? And that's all to it.
I prefer the PS3 for the series of games I love and follow and for the Blu-Ray and motion sensor, and I don't care if you prefer something else, it really is preference. However, if you guys can't stop arguing about the technical differences because you think one must be better although you really can't tell which, get yourself some more money and build a goddamn PC, that'll shut you up.