SEO Cheat Sheets and SEO tools
I recently came upon these post by SEOmoz and thought I was great so I did some digging around but I thought I would add some extra notes and hopped you might add some more.
SEO Cheat Sheets
Keyword research tools
Link research/development tools
www.influencefinder.com a tool just for finding links
www.brandwatch.net yes I know it is a social media monitoring tool but you can use it for conversations and places to find sites to link from.
Please do add yours in comments.
See also http://www.seomoz.org/tools