PC differences

A friend of mine and myself got into a discussion of PCs (since I'm looking into getting one) He is of the school that there is no difference it just carries current, I of course disagree. Can the forum members help me with this? I admit I don't know the difference in Litz, sold or multi strand and why it creates such spectular differences. Also why is cryo treating also causing such a s buzz? I have an idea that it forces a stabialization of crystals but i need more help for that. Also for a cable to present a netural non colored difference, why do the camps differ so much between silver, high purity OFC and hybrid designs ex: silver over HP Copper, or Gold over Copper? I can understand differences in materials. And lastly why does an after market cable make such a difference? (opinion only; they ALL should be UL listed, it's an insurance saftey thing) Is due to resistance, voltage transfer or what? I know it's alot but learning is always helpful (just need it in some more simplistic terms please) Thanks to everyone.
I agree with audphile1 the biggest improvement I found was with my CD player which is Sony SCD-1 with a PS Audio Statement Extreme.The improvements were a lowered noise floor and a much blacker background. I have the same power cord on my amp and have not noticed much of an improvement. However, I did not experience a degredation in sound quality as audphile1 did. With my pre-amp no difference was experienced again utilizing the same cord. As a side note my Amp and Pre-amp already came with decent power cords with hospital grade ends so maybe that is why I did not experience much if any improvement. I did not experiment with differenct brands of cords so I can not comment on the impact a different brand might have. So in general your friend might be correct depending on the quality of cord your equipment came with.

Hey Chuck, by the way I did return the PS Audio cord. Thinking what power cord to get next for my amp jus because it came with a 16awg cord and I think bigger awg cord such as a 10awg, wouldn't hurt. But at this point, I am not a big enthusiast for an amplifier cord. Well shielded AC cord, in my opinion, will have greater effect on a digital front end then on the amp. At least this is what I've able to determine in my system. Bigger difference, I would think, should be expected of a good power conditioner such as Shunyata Hydra then of any power cord...
Thanks to both so far, I am in serious conflict between VH Flavor 4, Signal Cable Magic Digital and Cryoparts Beast. Thay all are a great value but it will fall on my ability to manage the funding (even though they seem relitively inexpexsive) and reap the largest benefit for my expendure but input form all helps.
Rsjm80, since you are obviously looking for some improvement in your system's sound, why not consider a decent power line condiotioner instead of a power cord. I am not talking about strip surge protectors, but something better, like Shunyata or PS Audio. It will provide for more improvement then a PC.

I have read positive comments concerning Elrod power cords on amplifers. Never tried one so I can not comment directly. They are expensive at least more than the PS Audio Statement Extreme. I have a UPC 200 passive conditioner with questionable discernible improvement. I bought it primarily for its surge protection capabilities as I do not believe I have any serious / audible power concerns. Maybe I would hear more of a benefit from an active conditioner such as a P500 or P1000.