Ok, so my son is a sophomore in college and, yeah, typical dad sounding like I'm bragging, but he's a freaking genius. He's working on two degrees - math and physics - and this stuff is fun for him. I'm a little jealous. On top of just being smart, he actually works hard at it. Yeah, I hear it all the time, "That's your son?"
Anyhow, he loves music and I've been introducing him to audio basically as I'm learning about it too. I'll admit that I was somewhat skeptical at first about cables and wire and their affect on what I hear, but, being open-minded, I tried some things out and found out for myself. Hawkeye sent me some Audioquest ICs, and let me just say that I'm not going back to the cheap stuff. (Thanks Gordon!) I can only move forward from here, and one day hope to put together something really nice. Oh yeah, I also learned that all amps aren't the same either, although I never really thought they were. But, I've tried several now, and each has had its own distinguishable qualities.
So, back to my son. He's always been a skeptic about things, too, in that he never just accepts answers - he's always looking for that scientific or mathematical proof. Around the time that I was beginning to think of trying "better" cables, I repeated to him some of the things I had read on here. I remember saying something like, "these guys think that using different cables made to different specifications with different materials will result in an audible difference in sound quality." I was expecting to have a long discussion with him about this whether or not different wires change the sound. I still remember his response, "Of course they do [make a difference]. Why wouldn't they?"
Now, I no longer need any scientific reasoning to reinforce my belief - and not just because I've heard the differences with my own ears. It was so obvious to the kid who has always needed to see the proof first, without ever even having to see any.