I'm curious what your HD800 serial begins with i.e. 20XXX, 30XXX, etc. Because my pair exhibits the typical 6Khz peak with s/n 30XXX and do not find it objectionable with the relevance of detail retrieval. Both my Fostex TH900 and HE-6 offers brighter highs.
I was following the HD800 thread for a long time before deciding to get one and see what all the fuss is about. It is extremely convincing when a good recording is played rendering an image that is second to none. This is one of the most extraordinary achievement in HP. However, as far as detail retrieval, the pair I have is on par albeit slightly less than the two aforementioned hp.
This is a perfect case in reference to what could be described as 'our unique hearing' and that we all different. I also find a lot of other quality headphones brighter than the HD800. Different peaks affect different folks... But an irritating peak (for some) doesn't mean that the HD800 is the brightest hp out there.