HAVE CABLES EVER TAKEN YOUR SYSTEM FROM SOUNDING JUST OK TO SOUNDING GREAT? Experiences ?

...only when the prior set of cables was really bad, like cheaply made lamp cord, did I notice a change from something okay to something great. 

I have not heard any differences in any cables I ever tried. Based on my experience and demonstrated experimentation, not preconceived notions, I don't think cables make any difference.

Marginal compared to other changes. I'm still committed to my decent cables (DAC to Preamp, Preamp to Amp) but in my system, I do not hear much difference from power cables. Will likely sell the unwieldy ones off.