Music network is way to go. Just purchased a Sonos ZP80 and Controller. Works like a breeze!
Room for improvement, though. There is no way to know which file is actually playing - the Sonos system seem to choose randomly between duplicates in different qualities/bitrates. And that's a nuicance if you - like me - has no less then five huge hard drives with music libraries on them. Everything from lousy 128 kbs to FLAC and Apple Lossless files which sound identical to CD.
Another drawback is the inability to play 24/96. There are a lot of files out there in better then CD quality, and Sonos don't seem to care (but M. do).
Also, the controller freezes up more frequently than I like.
The Sonos folks seem to take music seriously, and I expect upgrades pretty soon. There are many other - and cheaper - options out there (Airport Express, SB, Roku etc), but Sonos wins on sheer convenience, expandability (and nice look, too). Kudos!

Current M-related equipment: DSP7000 (2), G91A FM, Sonos ZP90/ZP80 Zone Players, F80 (kitchen,yellow).