Seems this issue is often brought up. No sweat, sometimes reading through these threads provides more insight when some well-written remarks turn up.
I can understand the sceptics and moreover, have been one in the past and still am one for some things. Yes there are plenty of items that seem to be snake-oil to me (those magic rocks, pixie dust, shiny stickers) but some other things are not.
Much of what markl wrote (as well as MikeS) I agree with. I'm a big proponent of garbage in garbage out. I think detecting nuances (subtle or not so subtle) as well as large improvements often come with a refined ear. This is not the same as some with good hearing.
Take for example wine. Some wine is ludicrously expensive to this poor college student. I mean....50k USD for 750 ml of wine bottled 100 years + ago? Err....no thanks. But to others this is an hour's pay. To the rich, some may buy because they want to appear "refined" while others can truly taste the diffence between an award winning Lafitte red and a boxed red wine. Obviously that difference was purposely dramatic.
I have come to enjoy the difference between a Merlot and a Cabernet Sauvignon (my prefered grapes). Some years are better than others and some companies consistantly pump out better batches. Can my untrained palette detect the difference between a merlot and a cabernet? (or between copper and silver wiring...) why yes it can! Distinct differences in body, nose, texture etc. (similarly for the wire). Can I succesfully detect the differences between a 1000 dollar Merlot and 50k Merlot and a 100 Merlot? Maybe, but I bet it would be slight (I have tasted a very expensive Lafitte and it was awesome but I could have been fooled given the great foods I was enjoying the wine with, all matched perfectly and purposely). However, a true wine connoisseur could in spades describe differences, subtleties, aromas, deviations etc, that I am simply not equipped to supply. Is it because I am inherently incapable? No...(though maybe) but certainly this is because I lack experience.
Experience counts for a lot, the more equipement I listen to the better I am at describing sound and what I like in a musical playback system. Also, the longer one has with asystem the more then get to know the sound (this is assuming a "marklesque" listening, not the background listener or specifically the multitasker). From here it is much easier to pick out differences. I was once told that HD600's sound like HP-1's. That this person could not detect a single difference in the sound. He is young, can describe what he likes and describes it well, but for the life of me I can't understand how he can't tell the difference! Same thing has happened between RS-1's and HP-1's with a bunch of my friends, all of whom have been recently checked for their hearing and all scored well (they are all under 30 for those wondering). They simply lack the exposure. They sat at my system were wowed by the clarity, the resolution but otherwise they were like...wow yeah, they sound the same but cool! Such wonderful music.
Meanwhile, I am mystified. The same? Are they deaf? Not according to science, to their audiologists! Experience and exposure to a great variety of gear will benefit a listener well.
Now will there be a huge difference between 15k copper wire and 100 copper wire? Perhaps given the configuration, insulation etc, but worth the markup? Not to me...but to someone else perhaps. I think once one gets into the wire purity and the configuration of the wire + proper connection to the connectors...well then things should be equal. Thus...the ludicrous markup in cables is yes...oily.
That said, those that have never heard a lamp cord wire next to a well designed cable can't really comment, or better, if they can't hear the difference, perhaps they truly do need to experience the system in a more thorough manner. Seriously, it is not as if all those in audio are ridiculously over indulgent with their money. Moreover, there are PLENTY of folks who buy into the quality cable deal because there is a difference...not because they have more money than brains.
Finally, those who can't hear a difference between a pcdp and a quality player, have simply never heard a quality player. It's that simple. Changes in snap, palpable playback, resolution, coherency, bass, highs, its there and its real. For those that don't believe my doors are open to you. Come on by and we will DBT my cd player with my portable one.