Here's one of those rare products that actually lives up to its hype. The Ultrasone
HFI.650 headphones have been widely praised on various audio forums by users who seem to have an almost evangelical zeal. While such comments usually need to be taken skeptically, in this case they are right on the money.
Designed for recording studio and broadcast applications, the HFI.650s have one of the most naturally detailed and impressive sound fields I've ever heard from a pair of headphones. Even though they are stereo headphones, the HFI.650s create a kind of three-dimensional sonic image that allows you to hear deeply into the source material. It's a unique listening experience that brings out aspects of the sound you might never hear otherwise, enabling you to position sounds and instruments more precisely in a mix. They'd be terrific in a broadcast situation where you have to mix through headphones. And as a cross-check against a monitor mix, they offer such a precise reference that you may find yourself making different -- and better -- mixing decisions.