The WD TV series has always been competent at playing audio and video. The first versions lacked network connection but has now evolved into including even wireless (802.11n). The increasing focus on streaming abilities has also brought a full implementation of Spotify. With full i mean also the ability to make and update Spotify playlists, which most other implementations actually don’t have yet (Boxee, Squeezebox and Sonos). It has HDMI, Optical and analog output. It can play almost all audio formats from either an attached disk or one on the network.
What it don’t have yet is a powerful remote app that can remote all this from your phone or other without using a TV for its on screen display menu. If this non existing app also had the ability to control multiple devices as different zones, you would have a full fledged multi-room music solution which also could play video and other things as Facebook.
As it stands now, the WD TV Live probably has one of the most competent one zone audio player but cant even compete when it comes to multi-room and is also dependent on a screen for displaying its menu.