SEO Tools:

Google Keyword Tool
www.seomoz.org
Majestic SEO
www.WebsiteRankingTool.net - Website Ranking Tool checks your website's Domain Age, Google Backlinks, Alexa Backlinks, Yahoo Directory, Indexed Pages, Social Media Links, Compete Rank, Site Value, W3C Validator, Internet Archive and Google Bot Last Visit.
www.KeywordDensityTools.com - Having the correct keyword density is a vital aspect in the SEO success of a given page. Keyword Density Tool allows you to search the density of keywords in a given article or Website URL. For pages targeting just one keyword, it is good to have a keyword density of 2% or higher.
www.HostSEO.org - SEO Hosting allows you to dominate the search engine results for a particular niche. By building multiple blogs for the niche and hosting each of them on a different IP address, you are able to completely apply all SEO link juice benefits passing through the properties.
www.BestBacklinkChecker.com - Still under construction, Best Backlink Checker will examine all the backlinks pointing to your website. The checker checks the Top Level Domain (TLDN), Page Rank (PR), Fake PR, Google Indexing, DoFollow, Link Existence, Anchor Text, Inbound Backlinks, Outbound Links, In:Out Link Ratio, Link Juice Value, Domain, Domain Page Rank, Alexa Rank, Age of Domain, and the number of pages Indexed on Google of each backlink.