Personally feel after owning a PS3 since launch and championing it all the way, now I have a 360 Elite too, I say the 2 are pretty much equal in different ways and whichever you buy, you are gonna get a great console.
The games are pretty similar in quality (i.e. some better on PS3 due to extra capacity of BR, some better on 360 due to being easier to work with for devs) and both have unique features.
If I was being pedantic, then I'd edge the PS3 over 360 due to things like R, Internet, Free PSN etc - but as Coopz says, unless you use those things (and I now dont need too), then its much of a muchness.
Similarly, 360 getting Facebook, Twitter, LastFM - all nice to have, but if you never use them, then not really a bonus.
I consider myself really lucky (ok, I've worked very hard!) to own both