Always show details in the first open message of a gmail conversation. "Details" include the from: reply-to: to: cc: date: subject: mailing list: and mailed-by: headers. Works with the *new* version of gmail (as of Nov 7, 2007).

This only works with the *OLD* version of gmail. See <a href="http://userscripts.org/scripts/show/13700">Gmail show details new</a> for the new version. Always show details in the most recent message of a gmail conversation.