Personas for Firefox is a extension that adds lightweight theming to your browser.
This has got to be the extension of the year.
In this version, the Persona selector is dynamically loaded and populated from a JSON feed and all designs are loaded via URLs to remote resources. All changes to the browser chrome are applied instantly, with no need to restart.
Just click the little fox icon in the lower left, and choose your theme, and it loads and displays, BAM. Don't like it, choose another. There are a lot of them, and they will be opening it up for public development shortly, which means more and more to choose from.
Give it a shot and tell us what you think about it.
Mozilla Labs Blog » Blog Archive » Personas for Firefox <<< Download link at bottom of article.