It really depends on your personal taste. Unlike MacedonianHero, I grew up with bright sounding headphones and that is the sound signature I enjoy the most. Therefore HE-6 is perfect for me, and so are the Grados (not all of them mind you ).
I wasn't a fan of the LCD-2, but I did appreciate the neutral response and fresh approach to this niche. I am receiving an LCD-3 soon, so will look forward to comparing it with the other headphones I've got. The things I disliked the most about the LCD-2 were the: constricted and narrow sound stage + lack of treble + too much mids. However, there was the paradox that the instrument separation was excellent even though the sound stage was narrow.