Here is the first tool I have been testing and have been using consistently:
Back Link Watch
What it does: It crawls the web and finds out how many back-links you have.
If you are building links or someone is doing for you, you can monitor the progress on your own.
Keyword Research: Find popular keywords and see what others are using.
Google Adwords keyword tool and Google Trends
Current Keyword position: WMTips
(has plugins for FireFox and Chrome)
I am testing each tool before I post it.
I want to provide good tools for you to use on your own.
Google's Free Guide On SEO (20 page PDF)
Page of 101 SEO Resources and Tools
Search Engine Land
Top Rank Blog
Eric Ward's Best Practices
SEO Moz Daily SEO Blog
Ontolo's 46 New Link Building Resources
8 Point Checklist to Hiring the Right Search Agency(webcast 33 mins)
8 SEO Tips for Affiliate Marketers