Roku or Squeezebox for a PC, Apple Extreme for the Apple world.
Squeezebox is rumored to have a better built in DAC for better sound out of the box and costs more. Roku costs less. I use external DACs with Roku for best sound. Many do with Squeezebox also.
Also Logitech seems more active in releasing new versions of Squuezebox these days whereas Roku Soundbridge design has been more static. Newer higher bandwidth wireless N support might be useful if Logitech provides that yet and your Wifi router supports it, but Wireless G works fine as well and costs less.
Squeezebox is rumored to have a better built in DAC for better sound out of the box and costs more. Roku costs less. I use external DACs with Roku for best sound. Many do with Squeezebox also.
Also Logitech seems more active in releasing new versions of Squuezebox these days whereas Roku Soundbridge design has been more static. Newer higher bandwidth wireless N support might be useful if Logitech provides that yet and your Wifi router supports it, but Wireless G works fine as well and costs less.