Toggle Headers In Mail.app
I want the headers in Mail.app out of sight for the most time, but once in a while I want to see if there are other people in the To: field, or I want to see the full Subject:, because it won’t fit in the table view.
There’s a keyboard shortcut to reveal all headers, but that’s not helpful, so I wrote a simple AppleScript that toggles the default set of headers on and off. Name it Toggle Headers___ctl-h.scpt and drop it in ~/Library/Scripts/Mail Scripts, then choose “Update Scripts Menu” from within Mail.app and you’re all set for toggling.
Update: Or, rather, don’t use Ctrl-H as it sends emails to the trash if you have the table view in focus. (The filename determines the shortcut, unless that wasn’t clear.)