Over a http://www.linuxdevices.com they’ve got an exhaustive article on how to build the ultimate Linux home music server using a small Linux PC, not dissimilar to the Zonbu.
What really struck me, after reading pages and pages of the article, was one of the final conclusions.
This is the author of the article speaking, not me (my emphasis):
I started this whole project before discovering Real’s Rhapsody client for the N800. I believe that Rhapsody is the “killer app,” not only for the N800, but for all small web tablets. Mobile phones someday too, maybe. But I honestly don’t know if I would have bothered to build an elaborate NAS-based music system, had I had Rhapsody on the N800. Why even store your own music, really?
I’ve been preaching this for a while. Rhapsody is a killer app for the Zonbu…
Hey Zonbu, if you included some level of Rhapsody content in your monthly fee I think it would be a much easier sell.
If you haven’t tried it, I can’t be more emphatic. If you like music, it’s the best money you’ll spend all year. For the cost of a single CD a month (nothing for a music fan) you can have an amazing, index library that recommends tracks and adds new content daily.
Yes, it really is that good.
-Mr. Zonbu
Real life with the Zonbu Mini-PC 
Uhm, so what is Rhapsody actually? I’m kind of ashamed to admit, but I have never even heard of it until I found your blog..
Ah, right, never mind.. Whatever it is, I can’t use it anyway..