What is an excellent power cable?

Have you looked at Isotek?

Look at Zu Audio A/C Mission or Birth cables.  I have replaced all A/C cables in my system with Zu Audio Mission cables.  Exceptionally well constructed and was an amazing overall improvement to my Pass and PS Audio stocked system !   Save some $$$'s and try them out .  ( Save even more by getting them through bids on eBay direct from Zu !!! ) 

Some older Shunyata's (Diamondback, Copperhead) have come down in used price to new-Pangea levels.

How are wireworld, voodoo, and crystal cable? 

There are just so many. It seems daunting.

@xenon There are many, many options. But it doesn’t have to be "daunting."

I recommend borrowing two or three from your dealer or an audio buddy or from a lending program like the one offered by The Cable Company.

None of us can tell you what you will prefer and what will work for you in your system. The only way forward is to experiment and learn and come to your own conclusions. All the best.