Suggestions on Better Server Setup than Mac Mini

FWIW, I use a Vortexbox Appliance, available from Little Green Computer.  It runs on Linux and uses FLAC files.  To batch convert your music to FLAC, I recommend dBPoweramp.  I currently stream the Vortexbox over my home WiFi network to my Squeezebox Touch, but I am sure other streamers will work, as the Vortexbox is DLNA compliant.  I think there is a list of compatible gear at the Vortexbox forum.  This is a very economical way to go, if not necessarily the ultimate in performance.  But I can't complain - my files sound great on my system.

Just build your own.

Happy Listening.

One thing about the Mac Mini is you can improve the sound  by adding a Uptone Audio Regen and Audioquest jitter bug. Total cost: $225.

I have tried almost everything (pc/win, Mac, streamer, Jriver, dbpoweramp, iTunes, etc. just to name a few -- audirvana on a Mac that has been simplified down (headless operation) is hands down the best value for audiophile grade (cost is no object excluded). I'm using Resolution Audio Cantata DAC (also supports upnp which I have not tried due introduction of network jitter). Especially with the audirvana iPad app it's great.  Audirvana on a Mac mini is extremely stable/ reliable and if you're having issues it's likely due to needing some maint/updates, disk rights verify/repair (specific to Mac OS file system), or a reinstall of OS X.   Don't bother with iTunes - it makes your library difficult to use with any other down market systems like Sonos, Roku, slim, etc. you may want to use elsewhere in your home. Plus it's much easier to manage files of differing grades (44.1 vs HD or Dsd) for different players in your home (or mobile devices) on a NAS.  That way you can keep audiofile grade files in separate folder - audirvana will pull in to library from multiple source folders.  After all this, I recommend simply managing your audiophile grade files very persistently and just simply using the Apple Music streaming service anywhere else you need music. Regarding audiophile grade source files, I either buy from hdtracks in 44.1/16-24 bit or higher in AIFF or if not available I buy the cd and rip it using EAC exact audio copy.  Once ripped, I've had great success with MediaMonkey for managing file tags and album art.  From many A/B comparisons I've done, AIFF sounded best compared to flac  (I also found aiff equivalent to wav, but wave not taggable). The next level would be to use an SSD drive and external power supply (see mojo products for Mac mini).  This is a very broad and complicated topic that with some key principles can be demystified and simplified for great results. so feel free to PM me if you would like to have more details. I'm traveling, so I can post some links in a few weeks for the Mac setup points for trimming it down. 

It's amusing to read posts here from people who are suggesting tweaks to the OP to improve the sound, when the OP has made it clear that sound isn't the issue, but reliability.
  The OP is fed up with trying to make a computer work as a music player and he/she isn't alone.  I also did the Mac& Dac route and have ditched it after a couple of years for a dedicated server.  Bluesound isn't perfect but on the whole has given me a lot less frustration than my previous set up.
  If the OP still has his original CDs, the simplest solution would be to buy something like Bluesound and re rip them.  If not, I am wondering if ALAC can be converted to FLAC.  Bluesound will recognize his current files and play them but I am pretty sure they need to be in FLAC