Best way to hook my new iMac to my PS audio PWDAC2

I just got a new 27" iMac I'm wanting to consolidate all my music into this one computer. I have a Mac mini which has the bulk of my library (about 10,000 albums) and it works fine but the new Mac is so speedy and is what I would use to download any new music. I have an Apple TV for the input now for the new iMac and the mini is connected via USB. The iMac would need a length of about 2m to reach the DAC. Not sure what is best USB, Ethernet, USB to spdif converter etc... I assume the Apple TV is the least desirable way to get music out of the computer and as far as I can tell it won't let me use a program like pure music or audirvana. I am for now dedicated to using iTunes as my playback software.

Thanks, Ryan