It is fairly easy to put together your own server (really just a glorified computer) that sounds good if you are comfortable building computers.
But it is a real hassle if you aren't, or don't have the inclination (I edited my original post as no one really needed to know about what I have built over the years - it isn't relevant here).
USB reclockers etc? Meh. Its the handshake with the dac that matters - and what it is feed. It is abit of a never ending journey in some ways...
Depends what you are trying to do, and how far down the rabbit hole you go.
Frankly - if you aren't into computer audio - I'd stay away from it and unless you have ripped your CD's already or want to stream. It can be abit of a cruel mistress, and there is always the next thing that comes along.
Streaming is very cool though. I love it.
As far as natural sounding transports go one of my favourites is a Pi Tracer. One of the best of I have experienced and relatively inexpensive. But there are plenty of others. Some great suggestions here.
For inexpensive servers I also like the Naim servers. They are good, esp with a separate psu. Excellent via BNC, which your dac should take. Great app as well that you can control via your phone/tablet - it hooks up to most streaming services. One of the reasons (actually the main reason) I like my wee Atom is the app & streaming.
I think you can even get one that rips CD's and catalogues them as well, if you wanted that.
Madfloyd is very experienced in this. I'd have a look at his system, see what he has done - getting some tips off his journey wouldn't be a bad idea. And AL. M - they will have jumped through most of the hoops already.
These days - for me - simple is good.
Hope this helps.
@Andrew S. - thanks for your extensive write-up and pointers to some folk who have gone done the rabbit hole with computer audio!! I am not much of a DIY music server person and I can see how the constant tinkering can be fun for some. Unfortunately, I am semi inclined to DIY but mostly don't have the time to tinker with it.
Pi Tracer - are you referring to the 47 Laboratory 4704 PiTracer CD transport?