As I've alluded to elsewhere, triggerhippy is right. Gotta b xBox, PS3 online is at best average. Yes it's free and xBox Live is £40, but believe me you really do get what you pay for.
I think the main reason I'm swayed towards the PS3 is the blue ray player as I do love hi-def films and my blue ray player is a rather cheap one which could do with replacing imo.
Decisions decisions!
THe PS3 Blu (not Blue!) Ray player is only average by todays standards, it was pretty good when first released and was an added bonus that the Xbox didnt have. As an all round package and a gamers machine the Xbox is better especially if you intend to play games on-line, the Xbox servers are streets ahead of Sony's, possibly why Sony dont dare to try and charge for using them! Dont be swayed by the Blu Ray player they are cheap as chips to buy now!
I own both and 360 here for me too. Pretty much my only reason for turning on my PS3 is to watch Iplayer and the like but with that arriving on 360 in the very near future it may go a long time without being powered up.
ps3 is what i'd go for, and i have both, the online isnt great unless you have perfect connection, but other than that i personally think playstation 3 is a better console than xbox 360, the blu ray just an extra, i dont even have any of the blu ray dvd's