Adriel,
Very good points from you. I agree with almost everything you have said in this thread. As a former (read: reformed / recovering
) hardcore audiophile, I have gone through the various phases of analog/vinyl superiority, high end cabling, tube amplification, etc. and have basically had enough with all the crap from both extremes -- the quackery addicted audiophiles with complete disregard for the laws of physics and psychoacoustics, and the pure scientists who refuse to acknowledge anything that he can't measure on his oscilloscope or prove with a FFT analysis or rigorous mathematical theorem.
You hit the nail on the head particularly with 2 points: (a) the Achilles heel of most CD players is their analog output stages, not their DAC's; and (b) implementation of both analog and digital reproduction technologies is usually the limiting factor -- not the inherent merit of the technology itself.
Nyquist
I know the theorem. It was popular when CD players first became popular. 16-bit, 44.1 kHz audio, they assured us, could capture every single nuance well into the 20 kHz limit of human audio perception. But if you have ever heard SACD or DVD-A, you will swear that this theorem is bullshit. Now, the theorem may be valid, but the few SACD and DVD-A players I have heard sound noticeably better than the vast majority of CD player I have ever heard. This could be due to inferior analog output stages in most CD players or a host of other factors, but I have to wonder whether CD's sampling resolution is really enough. Maybe SACD and DVD-A give you enough "spare" resolution that if your implementation of the digital reproduction process is flawed (and it usually is for affordable players), you can get away with it and still deliver great sound.
Analog/Tubes
They are less accurate and less practical than solid state amplifiers, but I find they do sound better in some cases, and generally like their sound. Remember, just because something is newer and technically superior does not mean it sounds better. There is a subtle warmth, sweetness, and spatial quality that you just have to experience to understand. Great with jazz and vocals, I find. If you've tried it and don't like it, that's fine. But to brush off tubes as old and inferior technology without listening to it or simply because it produces more distortion, less power, and is not as practical as solid state without listening to it... well, you're missing out on a wonderful experience.
Tannin,
I agree about transducers being the weakest link in the audio chain on a macro level. This is generally true, but we have found that amplification and output circuitry continues to be neglected in "mass market" audio -- almost to the point where it is competing with speakers as being the weakest link in the audio chain. Many mass market audio components use cheap IC's and op-amps in their output stages that mangle the audio signal going through them. Power supplies are often poorly regulated and undersized (notice a similarity to vomit boxes yet, Tannin?). Negative feedback is used to mask distortion caused by poor circuit design or cheap components. Power ratings are what sells, so companies will sacrifice sound quality to get a higher wattage rating (Technics Class H+ receivers come to mind) (notice a similarity to external data rate / interface bandwidth numbers here?). Believe it or not, but electronics (the vomit box type you find at mass market stores) are much more of a limiting factor than you think.
Now, since you have brought up a good point about the mechanical limitations of transducers, and the variations/imperfections in the 1-3 dB range, let me bring your attention to an even greater limitation in audio reproduction and psychoacoustic perception: the acoustic properties of your listening area.
Due to the nature of room interactions and standing waves, the acoustic properties of your listening area can introduce variations/imperfections in the 2-10 dB range. Speaker distance from each other, to the walls, to your ears, horizontal angle to your ears, vertical angle to your ears, distance of your listening chair to each wall, reflectivity/absorption characteristics of every mass and surface in your room, etc. -- these can all make signficant (tens of degrees or several decibels) differences in phasing and frequency response at "hundreds" of frequencies.
Of course, this would require rearranging your living quarters around your sound reproduction needs, as well as using unsightly tube traps scattered throughout your room... which is far from practical. But if you want to cover all your bases, you can't leave room acoustics out of any audio discussion.
Myself
So what do I do? That is the question, presumably, after listening to me babble like I know what I'm talking about...
Since I have had to move around quite a bit the last half decade for education and career, it was not practical to ship or buy/sell a room full of audio equipment. Also, I just can't seem to spend a couple hours every day sitting and doing nothing else but listen to music. I just don't have time for that anymore. So, I make do with crappy 192 kbps mp3 audio played through my crappy onboard Realtek 5.1 audio and crappy Klipsch ProMedia 2.1 speakers and call it a day. My "mid/high end" (well, compared to mass market stuff) equipment is sitting in boxes.
All I know is whoever originally stated that 128 kbps is equivalent to "CD quality" should have their ears checked.