Thanks for the feedback thus far. To summarize to my points, it appears if the Outlaw line of receivers and preamps in general can adequately drive most headphones including the Sennheiser's and Grado as well as at least some AKG and BeyerDynamics models.

A question about headphone imaging that possibly relates to Primaz not listening to headphones any more. When I was younger and my world was stereo only, I listened to Dalhquist speakers that whatever else their faults, imaged wonderfully. I remember being able to almost point to specific instruments in the sound stage. My current NHT's don't image nearly as well but are adequate for my current needs which are centered on video. The thing that I don't like about the headphones that I have listened to thus far (the iGrado's and a pair of high quality in the ear Shures) is that they don't have any sound stage. In the case of the iGrado's it seems that all of the instruments are in a point in the center of my head. The Sennheisers image somewhat better, but there is no front to back. Singers seem to be on the top of my head and specific instruments were on the right or left but seldom in the middle.

My question from all of that, is that the experience I am likely to receive from all headphones regardless of manufacturer or type? If so, I am more than likely to drop the whole idea. I am also clueless how headphones can provide directionality using Dolby Headphones, it they can't provide depth in a stereo image.