Headphones

I have both the Sennheiser 580's and 600's, the 600's are superior in midrange clarity, bass response, and comfort. Terrific headphones. I've used the 600's with all kinds of different gear, so far my favourite is a Grado RA-1 headphone amp. I'm sure many have had good experience with Headroom and Antique as well. Can't go wrong with 600's.

I just bought a pair of Sennheiser 600's last week for $250.00 new from hififorless!

I compared them directly to my Grado 200's (now discontined, close in sound to the hp-2's). The Sennheiser's are very sweet sounding in the top end, and are way less colored than the Grado's. On certain dynamic music, I sometimes prefer the Grado's, but I am always aware that this is a false and colored rendition of what the recording actually should sound like. Ironically, I was not aware of the Grado's shortcomings, until I purchased the 600's. The 600's are a true reference product, that at $250.00, are unbeatable for the price. (Note: The 600's also improved dynamically after about 48 hours of continuous playing)

I should also note that I owned a pair of Stax pros years ago, and miss them much more than I ever had imagined. These were $1200 headphones (at that time), that were not perfect in terms of ultimate low bass slam, and their highs could be a bit overbearing at times (this is why I eventually sold them).
Unfortuntely (and ironically) , neither the Grados or the Sennhesiers are as ultimately enjoyable to me. There was something about that electrostatic midrange purity, maybe it was the speed, that I really, really miss (regardless of the other pitfalls).

Good luck on finding the best headphone.

I have the senn 580's. I think overall they are the best I've heard. I do note that they have their drawbacks. They tend to sound a little 'too smooth'. Sometimes they are also a little 'too good' and tend to overpower you with detail. I find that at work I sometimes prefer listening to my old sony v6 studio headphones. They just have a relaxed quality and are a little easier to listen to as 'background' music. Some other bad characteristics of the 580's are that they tend to sound loud to others in the vicinity, and they don't have any sound deadening ability. You hear EVERYTHING going on the room around you. The sony's are much better in this respect.