I posted an entry on My MSN Spaces blog posted a quick thread in response to a request for advice on setting up audio. Net net (and no surprise given my past experience and affection for Roku Labs products), I like the Roku software and hardware combination approach, although the Sonos system is very slick and well integrated.
There is some great third-party software to introduce the concept of zones with Roku devices through third-party apps running on the master PC: one way to do this is through a handy application from http://www.cidero.com/. And there's also "Visual Media Remote" (or "VisualMR" for short) which is designed to be a compact, PocketPC controller.
Wish list: I would like to find a better-integrated solution with the Microsoft Windows Media Center PC... it'd be great to have zones control driectly from my 10' experience. Note to self to send a mail on Monday to the awesome Media Centre team (after checking the green button).