I have a Squeezebox 3 into a G91 using the SPDIF coax connection. G91 goes in analog stero only into a G57 into B&W Nautilus 804 speakers. For CDs ripped using WMA lossless there is no difference in sound quality vs the G91 playing the disk directly. G91 upsamples the PCM from the Squeezebox to 192 KhZ/24 bit for the analog outs of the G91.
Squeezebox does not deal with DVD-A, and ripping DVD-A tracks involves tracking down decryption software that was removed from the INternet by the RIAA's court injucntion and going through a dozen complicated steps and 3-4 other programs even if you could find it. So practically there is no DVD-A audio solution. BUt CDs are great.
It is the best $300 you will ever spend on you audio system. Just do it.
Sanjay