The last time I looked, copper was copper, there isn't two kinds, especially for the electrons to travel.
I'm not suggesting people should buy the ridiculously priced cables, but even in (computer) networking, cables matter. If you try to run 100Mbps Ethernet on marginal CAT3 rated cables, you will get errors on the wire. Of course, for speaker cables, keeping conductivity high is what matters. So I'm just suggesting that using a thicker cable for longer runs (with 4 ohm speakers) will make a difference. Just not $7000's worth!!!
For my HT, I bought the Axiom cables. It wasn't that expensive and it gave me a piece of mine. But for one of our store location (mostly playing CD/FM), I ran HDLC cables - Home depot lamp cord!
As for Mythbusters, I just don't know how they could test it objectively.
