I agree with the above posters regarding rock/metal on the LCD-2.
My previous highest quality set was the HD600. I still love them, simply amazing for classical, super balanced, laid back, delicious really. I enjoyed even listening to rock with them.
But the new toy, the LCD-2, simply adds another dimension to my enjoyment of rock music in particular. There's something about it, and I'm just gonna throw it out there that a BIG part of it is the way it renders rock drums, that just makes rock and roll sound electrifying!
My first 2 days with the LCD-2 were in a nice weekend, I couldn't take them off my head mostly, and later I found out that my feet were sore for some reason... weird huh? But then I realized why, it was because I was tapping my toes nonstop, the whole time. The rhythm, the drums, man! The bass of the LCD-2 is incredible, it has amazing extension, tightness, speed, and that adds to the rhythm because of bass guitar and bass drums; also the detail on highs like cymbals and hi-hat is the best I've heard so far. It all adds up to an amazing presence and realism in the drums that just makes it all a much more engaging experience.
LCD-2 simply rocks.
On sources, all I tried it with was CLAS+SR-71B, using ALO Audio copper balanced cable. To my ears it all sounds amazing; however I don't have any experience on how LCD-2s behave across multiple different sources/amps. All I know is the combo I have works spectacularly well for me.