Really nice Rated 5 out of 5 stars
Great addon, good editing and most important an Undo button. Recommend it to everyone taking web page screenshots :-).
Oh, and for everybody complaining it doesn't support Fx 8: a compatibility update is awaiting approval from Mozilla since November 17. You can download it from the all versions page, https://addons.mozilla.org/en-US/firefox/addon/awesome-screenshot-capture-/versions/.