I own the LCD2 and TH900 for comparison - heard the HD800 for hours before.
The TH900 bass is powerful, impactful that you can feel but not muddy at all and is well defined. I can hear all the subtleties of the sub bass note changes and rumble down to the limit of my hearing and feel bass I cannot hear. The headphone is every part as clear and detailed as a LCD2 with a bigger soundstage + more extended treble. The mids a slightly back/receeded but smooth and clear at the same time - a rarer feat. In comparison the LCD2 bass is very defined but is not as powerful as the TH900, however its midrange to bass balance is better and the mids are to die for. Unbelievably natural and euphonious.
The HD800 has less bass then the LCD2 - which is not bass light btw and has a very robust bass that runs even down to near 20hz low as anyone could hear. The HD800 is thinner in the bass but has great quality. The HD800 is a bright headphone obviously, and the LCD2 is a darker headphone with rolled off treble in comparison. The HD800 has a much much larger soundstage and is far more detailed/critical or recordings. The LCD2 is much more forgiving. The LCD has a thicker/more organic mid range.
On the topic of non audiophile reactions. I was talking to a visiting friend at my office about the AKG 812 and what we thought it may turn out like, after I got off the phone one of the employees here asked what I was on about. When I told him about my headphone hobby and collection he gave me the "you collect headphones and audio equipment, what on earth for"? "I don't think I could spend more than $50 dollars on headphones, I think mine sound pretty amazing personally". I told him that I'll bring my Fostex in with me for him to have a spin, and see what he thinks.