Thanks for all your recommendations. I gather these headphones work best with tubes, which is something I wanted to avoid but now am not sure I should.
It is difficult to make a decision without the opportunity of listening to the gear first -which is impossible here- and at the prices involved one really cannot afford to make the wrong one.
Based on your location and circumstances, I personally would go with solid state too. The Sein HDVD800 DAC/Amp is a little above your budget but maybe keep an eye out for a used one? Then, there's $900 Woo WA7 DAC/Amp which I have personally listened to. It sounds wonderful with HD800 but it's also a tube amp(much less tube rolling though)