I aggree that there are MANY ludacris gimmicks out there aimed at tricking people that their "magic rocks" or "snake oil coated copper" will improve sound quality. However, the persuit of aural nirvana is not all in vain! Having listened to many high-end headphones (Grado, Sennheiser, AKG...) and bookshelf speakers (Audioengine, Klipsch...) I can tell you that NO TWO SETUPS SOUND ALIKE! This infers two things: 1) that preference to sound is subject to opinion, and 2) that the "accuracy" (if defined by repeatability and standardization) of even the expensive systems is not all that great.
Build a headphone amplifier using precision, ultra low noise Op-Amps. After gaining an appreciation for how a particular song sounds, replace the Op-Amp for another (also high precision and ultra low noise). Both IC's will have an exceptionally flat frequency responce over the audible frequency range, but the same song will sound SIGNIFICANTLY different! Most engineers today have been accustomed to dealing with digital electronics, where you can take assumptions for granted. However, in the analog world, there are many more factors to consider than noise and frequency response... such as how the system responds to an input that consists of two simultaneous frequencies at opposite ends of the spectrum.
In short, audiophilles aren't as stupid as you may think. They (I am not one of them) know that many factors can affect the sound of their DUT; including but not limited to, capacitor type, conductor type, temperature coefficients, and alloy resonance. There is no such thing as magic, but there are still plenty of fields of science which haven't been discovered yet!