Rainbird on 10 November 2009
I can't really help you with the online question. All I can say is that I am completely satisfied with PSN, but I have never been near XBL, nor am I big on online gaming. In fact, I'm the kind of guy that would never pay for XBL.
Personally, I think the most important to consider is what systems your friends have. If that doesn't really matter to you, then it's down to the libraries of the two.
If you like games that tell good stories, then I can definitely recommend the PS3. Again, I can't compare to the 360, but the PS3 has some awesome and unique titles. I'll gladly give you some recommendations if you want. Also, if that is of interest to you, you buy PS1 games from the PS Store.
