I've said it before, but there's only good in repeating: Firebug is amazing. If you do any web development -- from poking at your blog template to building complex AJAX applications, you really can't beat Firebug.
And when you've saved hours, days, or even weeks worth of work thanks to Firebug, you'll no doubt want to head over to the site and donate to keep the dream alive.
Congratulations Joe. You've hit this one out of the park.