Search the archives as this question is asked two or three times a month.
I use a Mac Mini with cds ripped in AIFF to itunes and stored on an external hard drive. The toslink out from the mini feeds a Monarchy Audio DIP which in turn feeds a PS Audio DLIII dac.
FWIW, I think the PS Audio dac is the dac to get at around $500. Also, the sound is noticeably improved with the DIP. Good luck.