If you take a utilitarian approach to this issue the answer is simple and two folds:
1. if you can hear a difference between a $5.00 cable and a $50.00 cable, then congratulate yourself, as you have what we call in the industry a pair of golden ears and/or a highly resolving system - either or both are good.
(but then again Bob Carver demolished some of those golden ears and resolving systems....
2. If you cannot hear a difference between power cables - again congratulate yourself as you have saved yourself heaps of money (that could be spent on music) and the agony of sleepless nights thinking about the next best power cable.
So as you can see it is a win-win situation.