I'm running the latest nightly of RC2.
Anyway, I installed the Structured Blogging plugin (it was fine before), and somehow it locked me out of my Admin. I finally figured out what it was, deleted the plugin and all the associated files, and I'm now missing the top menu down to the post title box and the options at the side. The rest of the Admin works fine. I replaced wp-admin/post.php and edit.php with new copies and there's no difference
(Feel free to yell at me if this should go in the Troubleshooting forum)