Good review! Even though I disagree with a lot of things you bring up, specifically the midrange, treble and instrument separation, it's pretty refreshing to read a different take on it. Interestingly enough, I listened to the tracks you mentioned, and I found them to sound really good on my 600's.

Excellent, I'm glad you like it! what other headphones can you compare it to?

I will say I don't have a lot of experience with the more expensive stuff, but I have heard the K701 and NTH-100. In comparison, the K701's are very thin in the bass and lower-mids, and pretty shouty in the upper-mids. The treble is actually something I quite like, though it is much brighter and splashier. And the soundstage is very wide. The NTH-100's are a much thicker, warmer headphone than the HD600's, though the upper-mids may be bothersome for you. It also sounds more blunted than the 600's, and my unit had some QC issues. I want to try some other stuff eventually though, especially the ZMF Auteur Classic and Audeze MM-500. They sound like something right up my alley, but they're way over my budget.