I liked the Codex Search plugin for WordPress, but had another plugin that wanted to output up there in the upper right, plus I didn't want to have to visit my blog in order to easily be able to search without typing in "codex..." into my browser.
So, I wrote a quicksearch for Firefox! :) (Not it was hard though, lol. Took like 2 minutes.)
You can snag it right here (at the bottom).
Hopefully others will find this useful.
 Just realized that that WP plugin also searches the forums. If anyone wants that for Firefox, let me know. :) [/edit]