Napster CTO Bill Pence has written a pretty cogent answer to critics' concerns that Zune signals the end of Microsoft's support for its PlaysforSure DRM format (and therefore for the digital music subscription industry as we know it). He argues that Microsoft has every reason to develop Zune and PlaysforSure in parallel, the way they do XBOX and PC games.
Interestingly, the piece also has a thinly-veiled threat to Microsoft: abandon PlaysforSure, and the music industry may abandon DRM in return (fat chance, but I like his moxy):
the disappearance of an open platform could spell the end of DRM technology altogether, at least for digital music. Since I believe strongly that the market in the end must and will be based on interoperable digital formats, if DRM is used to erect barriers to that goal, then there is no question it will be swept aside, and the industry may end up with what many have believed was the obvious choice from the beginning: open MP3 files.