After Market Power Cables - Gold or Snake Oil?

Myself and a collegue of mine have been discussing the potential benefit(s) of using after market power cables with hifi equipment. I claim that since the majority of home owners gain their power from the everyday wall socket, how does the addition of a short length of 'expensive' cabling make any appreciable difference to the sound quality. Are we kidding ourselves and buying into marketing hype or is there some scientific truth to the matter? I am a musician/recordist who understands the fundamentals of electricity and sound reproduction.
Former PC Skeptic

A few months ago I bought a pair of VTL 300 deluxe mono block here on the gon. They came with 18 awg, computer type power cords. After using the amps for a while, I felt the PC’s and they were kinda warm. Not a good sign. Needing bigger PC’s I did the following.

I bought female Watt plugs from Then went to Home Depot and bought three sizes of CAROL Industrial power cord and Industrial Grade male plugs. The sizes were 16/3, 14/3 and 12/3. All the materials, including the Watt plugs cost around $100.00. Over a weekend I used each size cord for a few hours. There was an audible difference with each size. Power Cords do made a difference. I preferred the 14/3 cords.

Note: I have a dedicated 20 amp outlet.
A look at the archive will turn up the following two things:

1. The GREATEST benefits are obtained by running dedicated line to your audio equipment.

2. The benefits of after market power cords are much more readily apparent in systems with dedicated lines.
I just recently ventured into the after market PC arena. They sure do make a significant difference in my set up. I hear more of a difference upgrading my CD players PC than my amps. I have the Synergistic Classic MC on the Miles CDP and the the Synergistic MC with MPC on the Aragon 4004 amp. Just recently bought PS Audio Lab II's to compare to the Synergistics.
First off,thanks for all your responses. You have provided a lot of fuel for the friendly argument my friend and I are having. (fuel for him , that is!). For the sake of argument, let's look at a typical a/c path. Edison delivers 110 volts to your breaker box. That goes thru a 20A circuit breaker to about 50 feet of garden variety 12 or 14 guage copper wire. Said wire is terminated with a good quality 3 prong outlet box. Hot, neutral and ground are all securly connected. I don't see how adding 5 feet of any esoteric cable can possibly have any sonic benefit. It seems to me that finding an outlet 5 feet closer to the breaker box would provide as much of a theoretical improvement. If not more. *ASUMMING* that the power cord is at least as good as the house wiring.
Not snake oil. Too many folks say otherwise. In my case there is a difference in bass foundation and overall clarity. I have both TG Audio and Pure Note Sigma cords which are good values for power cables.