My first (like so many people) was a Netgear MP101 but sadly that died many moons ago.
Current setup is Squeezebox Classic connected to a Cambridge Audio Azure amp running against a ReadyNas NV+ for the server.
It was a sad day when Logitech abandoned all of the squeezebox hardware as it was all pretty good stuff, but at least the server software is open source and still under active development (albeit officially unsupported) at http://wiki.slimdevices.com/index.php/Nightly_Builds