Here are some SEO add-ons for FireFox which I think are worth a look 01 – SEO for Firefox 02 – SEO Quake 03 – KGen 04 – Firebug 05 – YSlow 06 – Foxy SEO Tool 07 – Search Status 08 – Flag Fox 09 – User Agent Switcher 10 – Web Developer Toolbar
Firebug was vital for me in working out how optimise a page by looking at other sites and understanding css,html etc a bit better. SeoQuake is good for off site seo in my opinion.
I think the best firefox add-on as nodofollow. Also I make use of the SeoQuake as it shows all the details about website that is PR, Rank, Age and price. Also nodofollow helps to check whether the site or blog is dofollow or nofollow.
I used search status plugin. it's great to tool with great features. I found this tool on the link below when I search in google. best-firefox-addons.blogspot.com/2008/09/searchstatus-126(.)html just delete the ( ) sign.
I'm using Google Shortcuts on Mozilla Firefox 3.6.3 Browser, it's easy to explore Mail, Reader, Google search, Maps, Calendar etc.