I've been using a mac mini for a while. It's easy to add drives and it networks well. You can rely on airplay to stream or use sonos if you prefer. I have mine connected to my TV for video streaming and use a wireless keyboard as a controller but the mini can be set up headless as well and you can use a number of different devices to control it.
Originally Posted by srf1
Mac Mini (as server) -> Squeezebox Touch, AE express->Cambridge Dacmagic Plus -> Outlaw RR2150 Stereo Receiver->PSB Image T^6 (dedicated 2 channel system)
Mac Mini -> NAD T747 -> PSB Imagine B, Samsung UN46EH6000, Panasonic dmp-bdt220 (home theater family room)
Macbook-> audio gd fun "b" dac/headphone amp -> audioengine N-22 amplifier -> audioengine P-4 speakers/Energy ESW-M8 sub/Beyerdynamic DT 880 (home office)