Get the PS3, I bought one and never going to regret it. Superior hardware then the Xbox and that's what counts for me.
I don't agree. The PS3 may have "better" hardware on paper but it's notoriously awkward to code for, the xbox 360 actually performs better on multi platform titles.
To me, the ps3 is a console masquerading as a pc, I already have a pc.
The ps3 may have been cutting edge tech 5 year ago but console gaming isn't about cutting edge tech, it's about stripped down, plug and play, laid back fun.
I was in the same position as the OP a month or two ago and I went for the xbox.
Both consoles have good and bad points.
It depends what matters to you, what gaming, to you, is all about.
The PS3 being awkward to code for, having low framerates and having an inferior controller were the main reasons I went for the 360.
Having said that, micro$oft charge you 24 quid a year for nothing more than the privilege of playing online, the ps3 is a one off payment with no subscription fees, has good support for video files and so on. Like I said, what matters to you? If you have a decent pc already, I'd go for the xbox.