I agree having music streamed is the easiest way to enjoy your full catalog of tunes at will. I haven't made the leap to AppleTV just have one iMac and several iPods in the house and the few times I have tried to use my Mac or an iPod as the source the music sound quality was very good, all my music is ripped at 320k and downloads are at 256. I do most of my music streaming via my NAS / Denon3808 and I have my music ripped to FLAC.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70