Thanks, again, all, for the responses.
While at the Newport Audio Show I ran into a guy who simply had a Dell notebook, running some music app (J River?) and he played it through a Schiit Bifrost (which I use on my iMac) and it sounded really good and he claimed it's really all one needs. Even Chris over at ComputerAudiophile prefers Windows over iTunes in his design of the C.A.P.S. 2.0 music server, and from all the feedback, it's right up there with the best of them.
I was seriously considering going the laptop route with the JRiver or at least trying Audirvana using memory playback on my iMac when I stumbled upon that old pair of Mapleshade ICs. Believe me, upon hearing the improvement, I truly feel that to get that kind of performance from a PC rig would require much more of an investment. I have no doubt you're hearing what you're hearing.
The sound I was getting via iMac was pretty damn good. At the audio show, all the computer rigs sounded great but nothing really trounced my simple set up at home. I thought I had it all. The only thing I heard that really bettered it was the MSB DAC fed by their CD transport. At first I thought it was fed by a music server but lo, it was just their transport. That was the revelation that stuck with me all this time.
I can't convince, in words, the level of improvement I'm at right now. All caveats and denouements aside. I'm still looking forward to something like an Olive music server that does it all without the trouble some seem to be having and I feel it will take some big name like Sony or NAD to come up with a trouble free unit that does it all: touchscreen selection, ripping, DAC, etc. Until then, I'm content with farting around with computer audio but my main, serious, and pleasurable listening will by with my TEAC PD-H600 cd player.
I hope PO doesn't read this.
All the best,