I think myspace is still a viable place for a musician to set up an online presence.
What Facebook has done to Myspace's social networking user base, Last.fm is well on its way to doing to Myspace's musician base. It's the same pattern, countering Myspace's rustic offering with vastly superior user experience and more ambitious functionality.
Anecdotally, I haven't logged into the Myspace account for my music project in at least 18 months. All the action's on Last.fm.