I just wanted to pop my head in here and say that, after having the LCD-2 in my studio for a while now, it is by far the most used headphone. I use it for everything--critical audio work, video games, movies, leisure listening sessions...etc (but only when I must use headphones such as late at night. I never use headphones during the day since my reference monitor speakers are significantly better in every way). I would say that the LCD-2 is used 90% of the time, and the only times I put on the other headphones is to get an alternate opinion on my mix/master. Even the Stax 007mkII hardly ever get used, not because I don't like it or that it's worse than the LCD-2, but simply because its sonic signature is less "full" and more "specific." I think the perfect analogy would be a full-body massage. The 007mkII (and many other headphones) are like have one or two masseuses working on your body at the same time, and they are targeting the important pressure points and muscles, but only limited to a few areas simultaneously. The LCD-2 is like having 12 masseuses working on your body simultaneously, and your are simply enveloped in a sea of enjoyment all over your body, from head to toe. That why I keep referring to the LCD-2 as "creamy" and "full-bodied."
The one criticism I've had about the LCD-2's slightly recessed mids still stands though, and that is the only reason why I bother to put on the HD650 at all--it's to check the mid-range on critical audio work. If Audez'e could fill that mid-range a bit, the LCD-2 would be just about perfect for me.
This is the EQ setting I sometimes use for the LCD-2 (only for material that sounds a bit too polite on the LCD-2):
This setting is what sounds "satisfying" to me (meaning I understand that it's not necessarily the most neutral, but I'm okay with it because it makes me smile), where the mids are more filled out (this is especially obvious if you listen to any song with aggressive distorted electric guitar as the main instrument, or a brass section during jazz or orchestral tracks), the treble slightly more detailed (but still quite natural and not fatiguing), and the bass slightly punchier (similar to the way HD650 punches), since I sometimes feel that the LCD-2's bass while weighty, doesn't feel quite a viscerally punchy as I would like.
There's another setting I created as the result of using a pink noise and then a testing mic through the hole of a CD that covers the earcup of the LCD-2, and then analyzed with Voxengo's SPAN spectrum analyzer, but since that's not exactly a high-end testing setup, I don't trust it and don't use that setting. Also, it sounded more fatiguing to me, which is my number one pet peeve. Now, what I wonder is this--if my testing is fairly accurate, then that would mean a perfectly flat mid to high frequency range would sound fatiguing, and the art of creating the ideal sonic signature is a highly subjective black magic, instead of simply scientific accuracy. But there's a chance my testing isn't accurate since it doesn't take into consideration the human ear canal's inherent resonance.
But what I do know is that my Klein + Hummel O 300D's are very flat, and after extensive acoustic treatment, further correction made by the IK Multimedia ARC System, and additional EQ'ing for the flattest response possible (with pink noise, testing mic at listening position, spectrum analyzer, and EQ), it is now the most amazing sonic signature that I just love. It's detailed, dimensional, rich, visceral, smooth, and the stereo imaging is just spot on. I cannot find a single fault to nitpick about, and it has made my heaven on earth (my studio) even more alluring than ever. My quest in headphones was always to try and find something that can sound close to the O 300D's, but now I realize it's just not possible, especially now that I have fine-tuned them to absolute perfection in my studio, so I no longer bother trying. I'm happy with how the LCD-2 sounds when I must use headphones late at night, and that's enough for me. It cannot compete with the O 300D's on any day of the week (and it shouldn't since the O 300D's cost seven times more), but it does make my neighbors happy. :D