Where will my powercables be used best ?

I agree with Bander's advice. I've tried the Shiva, Vishnu, Brahma, and Valhalla and would recommend them as your budget allows. The Brahma may provide the best value in the Nordost lineup.

As a general rule I think your better power cords would have the most benefit on the "front end" of the system - the power regenerator, the cd/sacd source and the preamp.

I'm not so sure putting the best power cord on a power regenerator makes sense. The regenerator I have...PSA Power Plant Premier takes in the dirty AC, drops the voltage down to a minimal amount, massages it and then re-amplifies the AC to 120/60. Based on that, why would you need a high end power cord to pass in junk AC ? To me, the regnerator just needs a heavy guage cord, say 10 guage at a minimum and not too expensive.

So many companies so many power supply implementations, the first post was spot on.

A few years back I tried 3 various price point PCs into a CDP and pre/pwr combo in different combinations. Improving the PC to the pwr amp made little difference, to the cdp as the PC improved so did the sound and the pre was the big surprise. Improving the PC made a night and day difference to the system performance. Over the years I've found that the only thing consistent is inconsistency when it come to PCs and matching them to the equipment they supply.

A bit off the thread. Someone here put a good power cord on his refrigirator, and you know what? Green vegetables turned red in a few hours. So what's my point? You never really know. In my limited experience the biggest change is with preamplifiers or integrateds followed by digital front end.