Why do AC cords make so much difference?

I'm another guy thinking the cords act as a band pass filter. A couple of years ago i read an article about using home electric wiring as the house computer network as well. The network signal was designed to operate at a higher frequency outside of the "noise band" on the power cable. high end power cords are likely to act the same way. THe question i have, however, is once you get rid of the crap on the power signal and you are setting with a pure 110 ac current why should there be a tonal effect. Bwhite has some interesting thoughts but i would think that the magnetic field of a large power transformer would overwhelm the effect of a magnetic field in the power chord. the lower inductance arguement stands up well for amps but for a low draw component like a cd player?? On the positive side the mystery gives the ole brain something to feed on