If the brightness of the HD800 is the problem, the Stello HP100 amp IMO does the job of amping them at a reasonable price (can be found at $300-400 nowadays used). It's more than powerful enough, has perfectly black background, great soundstage for a SS amp, strong bass, and most important of all has a filter switch at the back that rolls off the extreme highs. I personally don't use it in my rig but the difference is definitely noticeable (actual hardware filter here) and will definitely make your experience less fatiguing.
I do prefer my WA6SE over it for my HD800 but the HP100 IMO comes close. And the matching DA100 DAC already has quite a good reputation for its matching with the HD800 here on head-fi.
Edited by K_19 - 3/22/12 at 5:13pm