Itunes? Amazon? CD? Something else?

I'm looking for the best recordings. The more I listen (with good speakers), I find little things that either don't sound right or aren't even part of the song due to interference. Like when I use airplay. If you listen close, sometimes it isn't as good...sometimes.

My cable has music channels. They're "ok."

I also find I like listening to music in stereo, 2 channel, more than 5.1. I don't want all the music in the center. Hope that makes sense.