ATH-AD2000 would be a good choice, but you won't find them in the price range you're looking for. I heard these phones in various setups at meets and I thought they were very fast for dynamics and performed well with acoustic music, but their sound signature was a little bit too harsh for my tastes. Also, I thought they lacked a little bit of bass quantity, but I can see why many people like these cans.
I don't know if you have experience with electrostatics, but if you don't mind stetching your budget a bit, the SRS-2050 system would be my pick at 600$ new and much less if you can find it used.