If you are blowing more than 200 quid on this sort of solution, you need to be chained up if you don't get a cheap desktop and appropriate storage.
Naah, I've fiddled around for years with old PCs running as storage in the background and with NAS boxes which couldn't stream media by themselves. The end result was you always had to have a PC running somewhere on the network.
I wanted a software solution. I investigated PCs running Linux from Compact Flash, Mini/Nano ITX motherboards etc. Never found anyhting which would suit me.
But this is just what I want. Passively cooled, will stream all my media and will also stream internet radio and I can just plug it into my WiFi router and pick it up with suitable HiFi and radio devices such as my Archos 605 WiFi.