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

I would think IC to source equipment would make the most differace BUT not if all your other cables were of low quality. Then I would think any one of them.

My last thought on this because it probably is one of those questions where there really is no definitive "answer." Shadorne's post makes a lot of sense to me and I have long been aware of all the pitfalls he cites and how they can impact on a cable's performance and "sound." However, in a system that doesn't suffer from any of the deficiencies he lists (I don't think mine does) it still seems to me that there should be a rule of thumb on which cable is most impactful in terms of asserting its "sound" in the overall context of a system. Oh well, another forever open question...

Ok, everyone is right.....
Remember..Your system is only as good as your weakest link !!!!
They are all important, ic's, power, & speaker c's. Don't
let anyone tell you your cables don't make a difference because they do.
Yes, many different flavors & prices. Find the ones that work well to your tastes & your system. If you feel ic's to start, go from there. I feel the synergy is important.

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.