There is a lot on this forum lately about Rasp Pi but what about the Intel NUC. Is it worth the added expense? Do you get a "more professional solution" that is a completed unit with less fidgeting in addition to better sound? Feedback and advice deeply appeciated so I can begin a project.
I've set up a few of those (Intel NUCs)...
The easiest solution for you would most likely be to download "Daphile", burn it to a USB stick, and run from there. It's a full-fledged audio server solution, ready to run and easy to setup.
Runs really nice with an Intel NUC. You can make the Daphile installation "permanent" by later installing it to NUC hard disk...
OTOH, if you want something completely silent, with an external USB hard disk with music, I'd go with a "thin client" option - fanless, relatively cheap second-hand, and also works with Daphile - so, not too much fiddling with installation and tweaks.
You can also test Daphile on your existing desktop computer, just install it on a USB stick, and boot your desktop PC from this USB stick with Daphile.
No installation necessary, and no changes to your desktop PC... It's a nice and easy option to "test drive" Daphile without any changes to your existing PC.
There are other hi-fi distributions, but those usually require more fiddling.
Oh, and BTW - I'd steer away from Windows for this purpose (audio server)... There are several ready-made Linux distributions (Daphile being one of them) which are already "hot-rodded" for the best sound possible - saves you grief and expense with Windows tweaking and "optimizing"...