Ubuntu One Music Store pictured, will be powered by 7Digital
It was widely reported that Amazon would provide the backend for the Music Store, but it now looks as though 7Digital will be handling things instead. I'm not surprised, as 7Digital is actually available in more countries. Amazon has, for example, been promising to deliver downloads to Canada for more than two years, and still hasn't come up with the digital goods.
7Digital is certainly a strong choice, and their logo already looks a little Ubuntu-y (though I'm guessing that wasn't part of the selection criteria). Their store offers a great selection of music including just about everything in heavy rotation on top-40 radio.
Add the Music Store to the revamped default software packages, user manual, and other improvements and Lucid will be -- by a wide margin -- the most average consumer-friendly Ubuntu release to date.