This has been a very interesting discussion to follow!
I have come to think about these issues less in terms of some "absolute sound" and more as "is the system giving me as much of what the recording engineer intended as possible." As in, "Oh, so THAT'S what Paul Simon, Tchad Blake and Brian Eno wanted me to experience on that cut from "Surprise." My own rig has come progressively closer to this goal as I've tweaked and upgraded it, I think, although it's hardly take no prisoners/state of the art.
As for acoustic music, if a tweak to the system makes it more moving or involving, I'm pleased.
YMMV, of course!