Taym

It obviously comes with a battery: LP-E6. Same as for 5DMK III, 7D, and other models.

Too bad. Hopefully that will change at some point with a firmware upgrade. It's a small, not critical, but very handy feature.

I am a new owner of a 6D and I am very happy with it so far.Quick question: does anyone know how to change the default file name form IMG_xxxx.JPG/CR2 to yyyyXXXX.JPG/CR2 (where "yyyy" is obviously...

It does not seems so. Have you waited for the image to fully load? They do look out of focus before loading is complete, in your browser. :)