I have to amend my last. I now have a pair of Stax SR009s, and they are the best I have heard (with the exception of the K1000s sound stage).
btw if anyone missed it one of the engineers of the K 1000 has an account here and posted about its creation:
It goes for many pages
Given that my current all-time favorite headphone (out of what I've auditioned) would be the Stax SR-Lambda (original 1979 Normal bias model) due to a combination of comfort, excellence at presenting binaural mixes, and lovely midrange/vocal presentation, the SR-009 seems like the natural progression...
...but I didn't like the SR-202 all that much because of its recessed midrange and vocals, along with the higher clamping force of the Nova/numerical Lambda-series headband. There's a chance I could still be rudely surprised by the flagship Omega-series Stax models, though maybe they don't impart that grainy texture that the SR-202 did and wouldn't suffer as much from an EQ bump in the midrange if it comes down to that.
Overall, the SR-009 is my pick. I've heard headphones with even better bass (LCD-3) and headphones with an even clearer sound (Lambda PRO) but the 009 is just top-notch all round. Precise bass, transparent midrange, (IMO) flawless highs, all beautifully even and balanced, excellently defined soundstage and sweet detail retrieval without ever sounding analytical. They have no "flaws" exactly, although I know people who prefer the warmer sounding 007, calling it the more true to life. Myself I'm not sure, the 009 just sounds more realistic to me..
Top that with world-class comfort and a build quality/design that makes every other headphone on the planet feel cheap and it's hard to deny the excellence of this product :)