Any high quality music servers out there?

I'm experimenting with an Apple Airport express. I'm trying out my buddy's airport express and connected it directly to my pre-amp, streamed the music via Itunes from my PC upstairs and I was very impressed with how it sounded as compared to some other units I've owned before such as the Turtle Beach Audiotron. My next step is try using a digital out into an external DAC. The deal breaker, at least right now is I would get significant drops in the audio over the wireless network. This type of solution is what will get me to seriously consider a hard drive based music store. I don't want a PC, no matter how you wrap it, sitting in the rack with all of my audio gear. I'm going to upgrade my network from 10Mb/s to 54Mb/s and see if that clears up the audio hiccups. I agree with Pardales that spending multiple thousands on a audio branded music server is not worth it at this point. My biggest concern about any of those type of machines is one of growth. Is there room for additional drives, etc. What happens when you burn through the 300 GB?

Kennyt: Thanks for the airport info. How certain are you that the airport is not doing something like digital -> analogue -> back out digitally, which seems like that would defeat the purpose of using a digital out. The reason I ask is it appears to me that the AE only has one output jack and you buy a cable with whatever type of connection you want on the other end ( RCA or optical). Like I said I happen to have my buddy's that I'm trying out so I haven't researched it much. It's a very slick solution though and really want it to meet my needs.