Interesting topic...
I've been a skept at best for all fancy cables - interconnect, speaker, and power, etc. I firmly believed the basic physics and engineering parameters such as inductance, impedence, and capacitance should only govern the performance of any cables.
In my recent first hand experience, I have realized that human ears are remarkable instruments that can respond to sonic characteristics way beyond the parameters I can measure with the modern test equipments. Having different speakers cables for a pair of 4 ohm Maggies made a difference in sound not only to me but others in the room and the long interconnects I was using at the time did change the sound characteristics when replaced with more fancier cables from a well known company.
On the other hand, the power cables are still unproven mistery to me. I would tend to lean towards adding active power filters over changing wire gauges and geometry. But then again, what the h__ do I know about the wires anyway...
Ki