Have tried them all now, after reading all of your fine reviews,,,,, whew,,, what an experience!  HD-650, DT-990, AK-702, AD-2000, AH-D7000, and of course the HD-800.  First, I am in complete agreement with SKYLAB's review,, remember it's mostly positive and I will write more later.  My initial impressions?  Give me the AH-D7000 with it's wonderful smooth, articulate mid definition, and a bit less "over" bass, give me the even consideration of the DT-990 with more of the air that the HD-800 offers and a whoop of the .AH-D7000 bass, and finally, please give me the HD-800 with all it's own built in delivery,,and a bit more of the wooomfy 7000 bass so low, even some of the even, comfortable wallowing serenity of the DT-990 upper mid definition ( that freq isn't  there in the other cans?)  and ,,,, I will have the perfect headphone!  I will sans comment on the AK-702 and the HD-650, neither of which I believe can provide anything near the "overall" package of the aforementioned.  The HD-800 is quite breathtaking, yet lacks in just these few areas. A bit anemic in the bass department, although very well defined. A bit over concerting in the high end register, just enough to muddle the middle a bit, enough to confuse it's awesome soundstage a bit.  Since I can't have it all? For the money. I'll take the DT-990, wire it up, amp it up and have a whole lot of fun and money left over. For a lot more money, give me the AH-D7000's too.  I'll still have some left for  an amp, and some extra cans for my girlfriend,  I am an retired sound engineer/recordist and performer, forced to headphones by proximity.  My Hi Def sound is in the closet.   DP
 
ps: something of interest,, the AH-D7000 is an awesome headphone but can be overbearing on BASS material.  try this, flip the left with the right and voalla!  Less boom and still excellent!!. It's that pointed driver config? Like having 2 headphones?