I currently own both, and I love both as well. I would say the PS3, but then again that may only be because I have more games for it. And the free online doesn't hurt either, although I do not care for paying for XBL. I still have my 80gb PS3, and she's running awesomely, had it since 2007. My 360 Elite is doing damn well too.
ccrogers made some great points. But I have no interest in that PS3 slim