I haven't seen this recommended yet so I'll weigh in: Ice Age Audio (iceageaudio.com).
I just purchased their "FrankenCable" power cords, along with their OFC speaker cables and interconnects. Because I replace all three at the same time, I can't attribute the difference I'm hearing solely to the power cords, but I was blown away at the difference in what I heard. Much better sound stage, and the clarity and detail in the music was mind blowing. After installing them, I started listening to some music to see if I could hear a difference, and ended up listening for hours. It was like hearing things for the first time.
The best part is that, compared to many other brands, they are MUCH less expensive. I can't say enough good things about them (and I also have to admit, I used to be part of the "can wires really make that much of a difference" school of thought).
I'm listening to music on an EverSolo DMP-A8 > Parasound A51 > Usher Dancer Mini-2 Diamonds.