SEO Quake plugin for Firefox

I am a Safari/Opera kind a guy, I guess I spend so much time making sure my HTML and CSS are valid that I only want browsers that read strict/valid code, but I came across this great Firefox plugin called SEO Quake that gives you a head start on competitive analysis. SEO Quake installs a tool bar in your SERPs that shows the # of pages in the directory for a site, the # of pages indexed on the site, the Google PR, the Alexa rank, the # of inbound links, and so on. Firefox may be slow, but this is a great tome saving tool for SEOs. SEO Quake even shows you the who is for the SEO guys that like to contact the owners for links. Check it out here