Computer audio (vs CD) seems to be the way to go in the future. I have created a sort of a poor man's Soolos with Windows XP computers, MediaMonkey, Airport Expressi (to several rooms for non critical listening)and a DAC on a PC for more critical listening.
Using free/very cheap software I am able to control all of my computers and different music being streamed to different zones simultaneosuly (via 10 a year old laptop). I can see album art, create/modify/edit playlists and view lyrics. All while in a chair with a small laptop (ie a big remote control) in front of me.
Usually I just have 1 computer sending music to 1 system at a time but it is trivial to send music to multiple rooms at the same time.
The expense basically becomes the cost of the harddisks as most folks already have a computer or two.