You will find that a number of members use a mini as a server. It works great, and with a SuperDrive attached (it's no longer built in to the latest version) is great for ripping CDs. Some will probably suggest you use add-on software, like Amarra or Pure Music, and there are probably good reasons to do so, but I just use iTunes straight up. I have an Audio Research DAC that I have attached to the Mac both by USB and through an Airport Express via a Toslink optical connection.
Personally, I think the Mini is the biggest bargain on the planet as a music server. If you have an iPod touch, iPhone or IPad, you also get complete remote control for free, if you have the mini connected to a wifi network.
Personally, I think the Mini is the biggest bargain on the planet as a music server. If you have an iPod touch, iPhone or IPad, you also get complete remote control for free, if you have the mini connected to a wifi network.