So I've been listening to my new pair of LCD-2s for a few days now and have, overall, a very positive opinion. Countless people have offered opinions so I'll keep them very brief for now.
I expected the LCD-2 to be fast and transparent, but I have to say they really impressed me in this regard especially. The only headphone I've heard that is equally good in this area is the Stax O2 Mk1. The transparency of the HD-800 is probably slightly lower, if I can trust my memory.
Although I find the term "grain" very nebulous, I definitely notice a lack of it in the LCD-2s. The soundstage is above average but not mindblowingly (or artificially) large and probably not as precisely imaged as on either the O2 Mk1 or my JH13. Vocals are really amazing. Beck's Sea Change in particular was by far the best I've ever heard it.
The bass is very potent but neutral. I don't think it's at all accentuated. I don't disagree with the claims of the LCD-2's great bass, but the greatness is purely in terms of quality - the quantity is neutral.
One thing I definitely want to mention is I don't find the LCD-2 to be remotely heavy. I mean, they certainly have weight, but I've been wearing them nearly all day while I've been browsing, reading, and so on, and the comfort is more than adequate. I don't find the clamping to be bad at all, nowhere near as bad as my HD-650's were when I first got them.
One more note: I've been experimenting with EQ. I do some production, so I have a high quality vst linear phase EQ, fabfilter Pro-Q, and I've been using it to add 3dB of treble based on my frequency response graph. I find any more than that fatiguing, but that amount adds a little bit of the "detail" and air that is slightly lacking by default. I feel much more comfortable adding treble this way than with a cable, amp, dac, or whatever. I am of course compensating with -3dB out to the overall signal within the EQ to avoid clipping. If you have a high quality vst eq on hand (I like linear phase, but that might be placebo effect) I would recommend trying it out with a vst wrapper. With foobar it's quite seamless and you have nothing to lose.
I listen at low/moderate volumes of 70-75 dB, so someone who prefers louder volumes might not consider them to be mildly dark and needing of EQ. I don't think that needing EQ is an insult to a phone, and to their credit, the LCD-2 respond very well to the EQ and have a smooth frequency response characteristic that makes EQing them quite simple.