For Reference the HD800's are it... As long as you don't listen to "fun" music
The HD800's are modern marvels and when I heard them (moded) at a meet I was taken back at how amazing they sounded but honestly for the type of music I listen to the LCD's and TH600's are the much better option hands down. Now the moded version that I heard was supposed to have better bass response which to me is bonkers that you have to alter a $1500 headphone so its bass is up to normal listening levels but that's a conversation for a different thread... The TH600's for the price are perfect. They lack in no area and will scale up with whatever you throw at them. I put about 4 different amps through that ranged from the Fiio e11 to the Pan Am and it didn't matter, they sounded amazing. Can that be said about the HD800?? I don't think so. You have to find the right amp that can pair with it well in order to get the best sound out of them. Not the case with the TH600's.
LCD 2's are closer to the HD800's as far as amping requirements but they still are great for all genres of music and the only real downside is the weight. I love my LCD's but the TH600's (to steal a line from boy Frank) curb stomps the LCD 2's IN EVERY POSSIBLE WAY. That's really saying something...
Thanks,