Hi-end PC audio questions

I am thinking about integrating computer audio to my 2 channel home audio system, either directly or preferably via streaming. Currently I have 4000 plus CD/SACDs and a high quality 2 channel audio system. Up to this point I have eschewed the idea of computer based audio files but with cloud and high resolution audio technologies and relatively cheap storage options, I am starting to have an interest. I'm thinking I may download all of my CDs in lossless format to HDD then access it from my network (and via cloud for when I'm not at home).

My question is, what is the best way to get it from an external HDD to my pre-amp? I use Apple computers and plan to buy an external HDD to save my music to, but plan for it to be in a different room. I already use iTunes but am looking at the Pure Music or Amarra applications to handle the file processing for lossless data. I have an Apple TV in the music room and have just purchased a Marantz AV7005 which has streaming audio capabilities for HT application, but use a an analog pre-amp for my 2 channel stereo needs. Currently all HT components, including speakers, are separate from my 2 channel. It would be easy enough to connect the AV7005 to the pre-amp, though if that was the solution.

If you have ideas, or can refer to an online source that would be great. Almost everything I can find is not geared toward high end audio sound preservation, which is why I am asking here, amongst audiophile brethren.