I agree that comfort and build quality are a huge issue with the HE-500. You really have to suffer for the music, and with mine I have to constantly tighten the screws holding them together or they will occasionally fall apart.
I think I want to demo the HD800 some day and see where it goes. I don't really like the HD650, I feel they sound very dry and papery and I am always aware I am listening to headphones. If the HD800 can fix these problems maybe I can find a nice used pair in my price range some day.
i like the "headphone experience" and as a student i honestly prefer having cheap mid fi cans and a lot of them so can have the luxury of switchinga round, I don't know of a lot of headphiles that owns some 20-30 headphones on a long run basis, I have owned them for almost 2 years and I will never sell any of them. I have returned he500 and x1 because they both sound the same and both feels too heavy for me. they rather don't have the intimacy and the mid range sweetness that comes with most my other cans either. Preference aside I really don't think anyone appreciates ton of wweight on their head. Me personally my jaws hurts from extensive usage of hd600 too, if i forgot to position it correctly. with he500 if I remember correctly if it hurts jaw there's no way to get it up higher on the ear. So is the case with lcd2.