for which purposes? each toolbar has some specific target? wanna know PR? wanna know backlinks? wanna know dofollow? wanna know alexa ranking? wanna know competitor? wanna know keywords density? etc etc...........
Google Webmaster and Google Analytics both are best tool for SEO activities. And Smallseotools.com it is also good for SEO.
Google Toolbar, SEOMOZ Tool Bar, and Web Developer Tool Bar is most important tool bars. and yes Firebug
hi, you can get various add on for your browser for SEO purposes. But all in one you can use Google toolbar for al your needs. Thanks.