I really don't want to get into this, but I just can't help myself. Personally I don't think any of the above mentioned reasons really matter, except the failure-rate. I don't see myself ever getting a bluray because DVDs will always be good enough. The rechargable battery for the 360 controller is worth paying for, because the controller is so fucking good, seriously, I think it's the best gamepad ever made. Having to pay for XBL is something that has been talked to death, you get what you pay for basically, a shitty, lifeless PS network or a guaranteed good time on XBL.
The thing that makes me prefer my 360 over my PS3 though, is the general design, and simplicity of the user-interface and all the little things that make it so much fun to use. Stuff like being able to talk to your friends over microphone while playing, or blasting music or whatever, and everything is so simple, there's no unnecessary bullshit.
Also, the popularity of games like Halo and GoW have made so many people buy the 360 that there are crazy amounts of people on XBL. I mean, whenever you see someone playing a console on film or TV, it's always an Xbox.