Which cable has most impact - IC, Spkr., power?

I think, the Amp-Speaker wire has to do a job for 2 tasks:
To deliver current and to handle the feedback from the chassis.
All other cables do the transport in 1 direction only.
Probably one reason why most experiiences agree with Speaker cable.

I would say speaker wire, I consider it almost a component in itself. Enormously important link in my opinion.

Shandorne's post makes a lot of sense but I have to agree with Joe also. Even assuming that one has the finest AC power and the perfectly constructed component, one would sense that one cable has a greater influence on sound than another cable. I am not an engineer, but are we saying that when one adds speaker cables, power cables or IC's to perfectly clean AC power and a perfectly built component, that their is no noticeable sonic change? If this is the case, than I have to believe that no component has ever or will be properly designed and perfect AC power does not exist. Since we haven't reached that point of perfection, It doesn't leave much choice but to pursue the pefection in another way. I suspect we are all going to be fussing with our cables and equipment for many moons to come.

To me it is pretty simple, the speaker cables are the most important, and subject to most interference, second is the interconnects, then last the power cable. 

now, if you were not using balanced ICs, maybe there is a more equal split between speaker cables and ICs.