To Anacrusis
I'm not so sure I agree with the statement about speakers varying the least. Being mechanical devices, they would tend to vary the most, at least to my ears. However, I agree that the amplifiers DO matter, and to a great extent, since they impart their sonic signature to the speakers. And, I have heard some combinations that involved excellent speakers being driven by horrendous amplifiers, with predictable results (acoustic agony). And I've also heard speakers that were not very impressive, improve markedly when hooked up to a superior amplifier.
When considering speakers, the quality of the design itself can vary greatly as well. Has it been designed to work under real world conditions, or just to measure well? How is the transient response and low-level information retrieval? How much noise does the motor assembly of the woofer make? (This can obscure musical detail.) How is the phase response? Will it sound good with a wide variety of amplifiers, or will you need to take out a second mortgage to power them?
As to the speaker itself, I have recently acquired what I consider to be the best sounding one yet, that sells for a fraction of much of their competition: Escalante Design's Fremont. At $15K a pair (increasing to $19K on 11/30/06 because of production costs), they absolutely blow away anything near, or at multiples of, their price. They are 'mega-monitors', and come with their own dedicated stands, included in the asking price.
Sonically, they are incredibly articulate and detailed; with loads of air, space, timbre, etc., but with a dynamic range that rivals live performances. Perhaps the most noteworthy aspect of their performance is not just that they sound good at all volume levels (they don't 'disappear' at lower volumes), but that they NEVER compress ANY part of the music, no matter how demanding the passage.
They are extraordinarily smooth, and pass on whatever characteristics the rest of the musical chain possesses. You could power them with a low powered SET (I've heard them with one), or use a super powered monoblock with wattage figures approaching a kilowatt. They are 93 dB efficient, and go down to 18Hz, CLEANLY.
As a long time advocate of planar speakers, since I am a nut for detail and imaging, it took a little time to adjust my thinking to having a dynamic speaker, but they are simply that good.