off topic... but i can distinguish between different bottled water
bottled water is inferior to canadian tap water imho
all this double blind testing stuff is like statistics all over again haha
off topic... but i can distinguish between different bottled water
bottled water is inferior to canadian tap water imho
all this double blind testing stuff is like statistics all over again haha

I have heard music through a variety of USB, speaker wire (14-16 AWG < 6 meters roughly) and RCA cables of varying lengths, brand, and prices. Did not hear a difference all else the same. That said, if there was poor contact I heard a difference: No signal. Same could be said about cables for video.
As far as headphones, I have tried a variety of them, and the differences in sound quality were relatively obvious.
The fact that I heard no difference across different cables and the fact that I see high prices on cables that made no audible difference to me (i.e. Monster at my bro's house) makes me a bit critical of them. Furthermore, I have a feel for how much capacity some cables have, and that makes me even more critical of them... compared to other components of a sound reproduction rig.
I did hear thumping and cracking through some headphone cables when running or when tapping them though: microphonics. But that's about it as far as I can think...
Comparing 16 gauge speaker cable could be taxing. Most high quality speaker cable is larger than 16G. Comparing typical Monster brand interconnects versus stock zip cord also could yield small results. I think for people who listen to headphones as much as the folks here, alot of the goals of getting better cable are not required...after all, the cans have their own connector and cord..plugged directly into the source or headphone amp. Not alot of changes to be made, except the interconnects from the preamp to the headphone amp.
There you go!
When I was a kid, selling bottled water seemed like a ridiculous idea, now it is a matter of taste and preference I guess.

Comparing 16 gauge speaker cable could be taxing. Most high quality speaker cable is larger than 16G. Comparing typical Monster brand interconnects versus stock zip cord also could yield small results. I think for people who listen to headphones as much as the folks here, alot of the goals of getting better cable are not required...after all, the cans have their own connector and cord..plugged directly into the source or headphone amp. Not alot of changes to be made, except the interconnects from the preamp to the headphone amp.
Why would the interconnects from the preamp to the headphone amp make a difference relative to other interconnects?
My main speakers are set-up well in their spaces. Takes a long time with bi-polar speakers. Equalization always sounds like crud to me. Just another layer of electronics on the sound. Even worse if it's in the digital domain. Good room treatments and speaker placement are important though like you said. A properly set up system shouldn't need equalization...unless you've got a really problematic listening room.
Digital and analog equalization can make a huge difference, and because of this it can either significantly improve your rig, or turn it into a horrible mess. It is therefore important to use a decent one, and to learn how to properly use it.
If you hear differences between cables then you are sort of applying equalization through them...
What equalizers did you use that made you shy away from them dude?

Even if you lead the horse to water, marketing always finds a way:
Hold on....I'm thinking of an Ice Cube angle on this... maybe water that freezes at 38°F?
Or maybe water that remains liquid down to 0°F?
ah, it's no use as the blatant violation of the laws of physical property/phase change would never allow us to get away with such nonsense...or would it? haha
PT Barnum strikes again!
This way to the great egress.

Hold on....I'm thinking of an Ice Cube angle on this... maybe water that freezes at 38°F?
Or maybe water that remains liquid down to 0°F?
ah, it's no use as the blatant violation of the laws of physical property/phase change would never allow us to get away with such nonsense...or would it? haha
PT Barnum strikes again!
just add salt and sell it for $100 a bottle... It'll taste different too. 
Regarding cables, I feel people don't necessarily "pick" on them per say. People pick on wild marketing claims, and overblown prices... and therefore become somewhat critical of audiophile cables as a result. Good information on how cables can affect things and how to choose among them is available. I found these articles useful when picking among them:
http://www.audioholics.com/education/cables/speaker-cable-gauge
http://www.crutchfield.com/S-sDemU6nctvW/learn/learningcenter/home/speakers_wire.html
http://en.wikipedia.org/wiki/Speaker_wire

So you think there is something about a cable other than electrical performance that can change listener perception but is not placebo/psychoacoustic? If the electrical signal is the same, then it affects the system and the sound it produces the same. That's the way it works. So what is this other thing that can affect listener perception and is not psychoacoustic/placebo?

I'm an EE so I can't say much about the medical field... but my father-in-law can. He is a retired medical doctor. He has told me more than once that certain things about the human body are not at all well understood (actually they are not understood at all.)
Cable seems a bit better understood in the sense that it is possible to predict performance and waveform integrity to very high accuracy. Listener perception is one thing, but if the waveform impinging the receiver (in this cause the human auditory system) did not change one bit from cable to cable, why conclude that the cable is at fault for perceptual differences?
AFAIK audio cables are electrical signal conductors whose function is to transfer electrical waveforms... That's it. Or does it do something else that produces a change in sound perception?
some people simply don't accept that there are any thresholds, that psychoacoustic Science has anything to say - because "everything" can't currently be explained - obviously their perceptions are resolving features "unknown to Science" in that "knowledge gap"
but to maintain that position they have to find a way to discount Blind tests, deny the rest of perceptual psychology results on how much our brain manipulates our sensory input, how secondary, delayed, edited, reconstructed from memory our conscious perception of the world is
when it comes to cable effects on electrical signal in our audio systems they have no idea of the relative magnitudes, even the dimensions of Signal Theory descriptions of microphone bandwidth, noise, or headphone frequency response, distortion, repeatability compared to expected, measurable cable "flaws"
