But at the end of the day, like you said, the HD800 really is most at home with acoustic music. With that concert hall soundstage, it really excels with live music too, which is where I feel the orthos fall short. It would probably make sense to own one of the current top-tier dynamics (HD800 or T1) and one of the current top-tier orthos (HE-6 or LCD-2) for that reason...if one's wallet can take that kind of a hit
Actually the Stax 507 is the best choice (IMO) for a "does-it-all" headphone within a realistic budget. It's well-balanced and does everything right. Maybe it's not the absolute best in every area, but it's much better-balanced than other competitors. I would rather have it than live with the flaws of the LCD-2, HE-6, or HD-800. I found the T1 well-balanced too, if not the last word in realism.
Regarding the LCD-2 discussion, I really like this headphone, but I don't consider it as realistic as its competitors. The tone is certainly beautiful and lush, and most of the time I found myself reaching for it over the HE-6. But compared to a real concert, the timbre and tonal balance are not as accurate as the senn, hifiman, or stax.