What is your best plugin for firefox that you are using in the seo process

I have installed on Firefox a plugin called auto fill form. It helps me with completion of the filling form on the blogs and social sites(name, e-mail address, website, title, description, password) with just a simple click i can post or log in. My question is : Are you familiar with other plugins, that is helping you in the seo process, saving you time?
Thank you.
Awaitng your reply.

For SEO analysis I use the following plugins, you can give them a try and report your feedback :
SEO Quake 2.6.8
SEO open 1.1
SEO Toolbar 1.1.3
SEO for Firefox 3.4.2
Rank Checker 1.7.9

Thank you for sharing it with me. i also have installed nodofollow, google page rank, alexa toolbar.I was browsing for addons and found seo doctor with whom you get the nodofollow included plus other like estimated number of daily visitors for a website. It’s a good combination. I read some reviews about seoquake…everybody praised. I download it myself and i will tell you how it works.
i saw a big difference between these two.Seoquake has over 1 milion downloads while seo doctor less than 100k…

I use
Flagfox- To identify the server status of a website
GreaseMonkey- To list the Google results with numbers.
Aviary- To take the screen shot of the required pages.

These are few that I use :

SEO Quake
Foxy SEO Tools
Swooty SEO Tools
DeeperWeb - Boost and Customize Google Search