Considering how easy it is to make/create new backs, I don't understand why people are complaining about it... look at what happened with the TP... everyone hated the gray, so they resorted to using dyes to color it themselves. Sounds like a perfect solution to me. I'm sure similar things will be done with the new one, so give it a rest on the whining, eh?
As for the headphone jack... AWESOME! Even though I consider it a PHONE, not an MP3 player... that's what my ZuneHD purchase will be for!