So I've lost all of my Firefox bookmarks (well not since 3.0) or history (3.5?) or my current session enough times (yeah... this still happens) that I don't leave my precious Firefox profile to chance, so I zip it up as a backup weekly. About a year ago, I unzipped one of my very old profiles because I had lost a session or something, and noticed that it still had active logins to all of my websites!
It was a long time until I realized that Firefox wasn't clearing cookies on exit like I had configured it to ("Keep Until: I close Firefox"). I also tried setting up "Clear history when Firefox closes" with "Cookies" and "Active Logins" both selected, and Firefox wipes neither. Eventually, I posted a bug on Bugzilla for it.
Now, I use my Settings Buttons extension to quickly open the Cookies dialog and wipe all of my cookies before closing my browser for the day. My question: is this any more or less secure than individually logging out of everything I log into to deauthenticate those sessions, or am I fine wiping all of my cookies?