PS3 is a better system in my honest opinion with features such as doubling as a Blu-ray player capable of 3D movies and free online game play.
XBox 360 on the other hand is better when it comes to controls and game selection. Not to mention almost everyone is on XBox live and not as much on PSN.
Last year, I kept my XBox and sold my PS3. I like my Xbox more but I chose PS3 on the poll.