I'm using Squeezebox Booms around the house but am considering getting a Squeezebox Radio or two. Be warned that there is an obnoxious virtual guide feature on the Logitech page which will talk to you unless you turn it off.

The Squeezebox Server application needs to be run on a machine somewhere in your house. It supports iTunes libraries but it won't do anything with DRM. You can also synchronise all the players so they're all playing the same content.