PS3.
http://gear.ign.com/articles/111/1116182p1.html
PS3 wins: CPU, RAM, and Hard drive.
Xbox360 wins: GPU
On Xbox360s' CPU, "Interestingly, the new combined CPU/GPU chip used in the new Xbox 360 is theoretically faster than the individual chips in older models. But in order to ensure proper functionality, Microsoft was forced to install a "frontside bus replacement block" that introduces latency and forces the chip to run at the same speed as the older model. This new combined chip may edge out the PS3's CPU in terms of reliability and temperature control, but no long term tests have been performed yet. "










