Reliability: The Xbox 360 suffers from the infamous "red ring of death" and is the console with the lowest reliability (23.7% system failure rate), according to Square Trade. Winner: PS3.
User Interface: The Xbox has had almost a year lead on the PS3, so it has a unique party mode feature and Xbox-style UI while the PS3 is slower and has the "generic" Netflix streaming UI. Winner: Xbox 360.
Of course, I have neither of these. I have an old PS2 that is never used. My wife keeps telling me that she wants a Wii, but it seems like a big expenditure for a platform that was aged the day it arrived. I also have my reservations about whether a Wii would be used after the first two months until my son is older.
Of the three companies, I would definitely prefer to support Nintendo. Sony and Microsoft are bullies and I strongly object to their business practices. That would make my decision quite tough. The XBox seems to have more ways to interact with your media while the PS3 opens the door to Blu-Ray. If I were to make a snap decision today I'd probably buy a PS3, at least I'd get a Blu-Ray player out of the deal if we stopped playing games on it, and it doesn't require expensive secondary purchases and online subscriptions to use it for Netflix.