Firefox users: Download Greasemonkey (latest is v 0.9) https://github.com/downloads/greasemonkey/greasemonkey/greasemonkey-0.9.0.xp... Then use this script to force Gmail to bottom post: http://userscripts.org/scripts/show/35866
Chrome users: Download the extension: http://userscripts.org/scripts/show/35866 It should recognize it and install.
Now you people have no excuse to top post ;)
-- later, Robert Xu