This article in Slate talks about the possible demise of stand alone music players and single function hardware (like the Kindle) in general.
What I (and many others) see coming is most likely a MOBILE iPhone-type computing interface that handles phone, photo, and Internet as well as a Kindle sized TABLET that does the same thing. The MOBILE may have to have some limitations, but who knows.
This is all media – magazines, newspapers, books, music, video, TV, movies, Skype, telephone – all through an interface that will either be pocket sized or tablet sized.
I think there probably will still be a place for a desktop interface, but this may just be a tablet on a stand that you can then pick up and carry around the house or office with you.