I have the same issue and it appears to be a conflict between Faster Image and Ozh’ Admin Drop Down Menu. When both plugins are activated, selecting “Add New” from the drop down menu results in a totally blank page. If you disable either plugin but not the other, there is no problem. Notably, though, the issue does not occur with draft or previously published posts.
I am using WP 2.8.2 and the most recent version of both plugins. The problem first surfaced in the 2.8 series, although I don’t know if it was with 2.8.1 or 2.8.0
