I suppose it isn’t an all-or-nothing deal, between myspace and the open web. After all, myspace is part of the web too. But I think trying to communicate to bands that myspace is only part of the puzzle is important; that myspace is a resource to actually drive more traffic to their own site, where they will gain greater long term rewards (if setup correctly).
For bands that care, I think they will see the benefit of this, if the benefits are made apparent and the tools are *easy* to setup.
Solid links to MP3 downloads, search engine relevancy, more streaming media, email listserv, paypal store, are all great benefits to having your own website.
Encouraging bands to create a rock solid online presence, while at the same time encouraging MP3 bloggers to link to the band directly, will hopefully lead to a convergence of ideas about how music can flow through the web.