I'd say either a HD650, but get it when it's on sale. They have been on sale a lot recently. Alternatives include the AKG Massdrop K7XX (When it drops again, which may be a while.), they can get away with not having an amp. A cheaper alternative could be the Sennheiser HD598. I would very strongly recommend an amplifier if you choose to go the HD650 route.
I've always found it in my brief listening to the HD5 and 6 series, and almost universally prefer AT to Senn for clarity, transparency, and detail. Since no one has mentioned it yet, I'll suggest you look into the AD series. I've heard a lot of good things about the AKGs as well, but haven't had the pleasure of hearing them.
Also because a lot of impressions can come under less than ideal conditions. Let's say ten people listen to the HD580/600/650 at a meet - by the time the third or fourth person gets to them the earpads would have been very compressed if they're not using brand new earpads and the headband wasn't bent into the proper shape (they're supposed to feel a bit like the K701 when worn, not the vise grip nor the tight pressure under the ears). With that you're going to end up with potentially six to seven people chiming in everywhere about a veil, and maybe two people saying the treble is kinda sharp but the midrange has a veil, all depending on how compressed the earpads were when they got to them.