Just sold mine. I've been agonizing over which to keep between the HE-6 and HD800 for a few days now, and the HE-6's combination of grain-free sound + the way it can handle any genre trumped the slight technical superiority of the HD800. Also, like MT said here, a slightly smaller stage just sounds right for some genres.
The HD800 simply did better though with perfect recordings. My interest in building a speaker rig is growing, so the HE-6 makes more sense as I invest in better power amps.
With your amp it makes more sense but the HD800 did sound good as well. I guess sound stage isn't a big issue for me other than if it is too small but I don't put a huge emphasis on that so the stage never distracts from the music for me. Then again you are one of the few on head-fi that wants only one rig since if I was you I would have kept both similar to my AD2k collecting dust.