I think the $20 winfire level gives you 384Kbps max, if you're within the optimal distance from the central office where the phone equipment is at. since the DSL will be provided through your local phone company, just call them and ask what your distance is and they can tell you what kind of speeds you'll hit most of the time.
I've got the free stuff w/ ads, and it's supposed to be 144Kbps, and my average speed is around there. might be a little faster if I didn't have those ads rolling in all the time.
if you go with premium level winfire, you can get max speed 1.5Mbps, no ads, free modem rental, for $35.
and it works great with napster. multiple simultaneous downloads each hitting around the max speed you subscribe to, assuming the user you're downloading from is running at a faster speed than you are.