What are the best SEO tools out there

[spider ninja]

Hey everyone, I'm building up a list for a client and need some suggestions on the best SEO tools out there. This is my starting point:

http://www.bruceclay.com/
http://www.wordtracker.com/
http://www.digitalpoint.com/

Any suggestions are appreciated. Thanks

[Jeka]

http://www.ranks.nl/tools/index.html