There has been a lot of discussion about the best transport and digital source. I have tried cPlay, Linux and many others. In the end, I settled on Mac OsX with iTunes and other programs like Pure Music and Amarra. The file management system with iTunes is impeccable. My music library with over 1000 CDs is right at my finger tips using iPad as my remote control. Using SoundHound, I can also get all information I want to know about the playing song instantly. Looking up lyrics is also a piece of cake.
I have a MacBook Pro with eSATA connecting to my hard disk. This is my reference. For my day to day music playback, I have a Mac Mini with USB connection. Both have been modified using SSD hard disk.
There are actually a few things you can do to optimize your OsX as well. If you search around, there are many free solution. But to make it easier for you, you can also pay for it. Here they are
It has been a few years since I ditched OSX as my digital source. I have joined the camp of Windows and I am now using Taiko Audio SGM Extreme. It is the best (no "one of") music server I have ever owned. Of course, it is also the most expensive one. But it performance is better than dCs and Esoteric system that I have heard before.
Moving on to 2021. I have upgraded my whole digital chain to Ravenna AOIP. So I need to use a music server that is capable to install Ravenna ASIO driver. One of the best server available in market is Taiko Audio and is windows based, making AOIP and option. It is an expensive move but well worth it. Emile is also helpful for literally realtime support!