Post your BEST SEO tool here.

Free backlink checker:

http://www.domain-pop.com/ - very nice if you have many links across a url
http://www.smartpagerank.com/pagerank-backlinks.php - also has many other nice tools

Key Words (helpful for PPC - Adsense, YPN, etc):

Google Key Word Tool - You can’t beat Google’s own keyword tool!

SEO Key Word Tool

Assortment of Web-based Tools

SEOChat - On left side

WebConf - many nice tools

Browser based tools:

–Firefox Plugins–

Smart Pages plugin - Very handy tool!

SEOQuake - shows nofollow links, along with much more

SearchStatus - Also shows nofollow links, plus much more

Alexa Sparky - Official tool for Alexa. Displays a nice graph along your bottom task bar. Also, helps to boost your Alexa rank (not very relevant unless you sell blog posts)

 

www.geoseo.com to check rankings ...

 

Thanks for sharing, great tool

 

I like http://www.spyfu.com and http://www.hittail.com a long with about 15 others sites I use on a regular basis

 

Well, Thanks for the nice tools you share with us its really awesome.

 

Some useful tools hereSEOMOZ Tools

 

thanks for sharing all these nice resources!

 

www.backlinkwatch.com
www.keyworddiscovery.com