Basically unless there's an enormously long cable or wire run or some sort of absurd unusual interference situation, there's no actual difference in sound from anything from Home Depot Wire up through the most expensive "premium" cables.
However, if someone has a stereo system, spends $100 on some premium speaker cables, and takes them home and installs them, they're ALWAYS going to THINK their system sounds better.
But when you take people have have them listen blind to the identical system with different $$$ cables, they can't tell the difference or don't pick the expensive ones as better than cheap ones any more often than vice-versa.
Basically, what happened is you had weenie anal audiophiles spending $10,000 on a setup, and then having the nagging feeling that the $10 they spent on speaker wire was somehow compromising the system - some clever people figured out how to exploit this psychological anxiety and thus the whole "premium cable" industry was born - with massive advertising in magazines, reviewers in audiophile magazines "reviewing" cables like they were brands of wine, etc.
The basic reality is that for any given sum of money spent on your system, any money you might spend on premium cables is far better spent on better speakers. For example, for a $1,000 setup where you're spending $400 on speakers and $100 on premium cables, you're far better off spending $490 on speakers and $10 on plain old home depot wire.
Speaking of speakers, the REAL fun used to start on the audiophile USENet groups when people asked about Bose.
This is absolutely true. For short runs you can use the cheapest available wire for speakers and you will be just fine.
For longer runs you have to be a little careful. The reason is that the resistive losses in long cable runs are frequency dependent and so this will effect the frequency response you get from your high end speakers. So as the runs get longer you have to go to bigger wire. Do a Google search for guidance.
For digital signals like HDMI you need to go to heavier duty and therefore more expensive cables as the runs get longer. You can find guidelines for this on the net also.
But as far as I'm concerned 80% of the bucks spent on Monster Cables is for "Pride of Ownership" and "Bragging Rights" and not performance. Monster Cable is the most over-hyped brand in the audio world.
They actually do and until you come over to my house and make a comparison listening to prove your point, I stand on my statement. /sarc