Based on Google search results of course, this Google tool shows you relevant keyword ideas and their Adwords competition for your website.   Related posts: Get New Keyword Ideas Stats On PPC Ads Monthly Keyword Search Volume

Spacky picks up searches from Google, Yahoo and MSN and displays them side-by-side. Works pretty well, but doesn’t pick up lower search volume keywords and phrases.   Related posts: Keyword Trends Google Keyword Search Tool Keyword Suggestions Tool

Find search volume of keywords and related keyword phrases with Wordtracker’s free keyword suggestion tool.     Related posts: Finding Keyword From Questions Keyword Suggestions For Your Website Monthly Keyword Search Volume

Type in all the meta info about your site, like author, location, cache control, designer and more at SEOChat and the generator will spit out the meta info ready to be copied and pasted into your website.   Related posts: Meta Tag & Keyword Analyzer Free CSS Generator How Hard

Find the strongest pages on your site in terms of keywords on SEOmoz. Free registration required.   Related posts: Show Related Posts in WordPress Link Popularity Checker Keyword Suggestions Tool

Wikipedia is widely popular – and has made its visitor stats available: Wikirank shows popular pages on Wikipedia which may suggest a trend on the web, or just on WIkipedia? How will you use it?   Related posts: Show Related Posts in WordPress Finding Keyword From Questions Keyword Trends

This analyzing tool shows lots of data, but seems most useful for analyzing metatags and showing keywords.     Related posts: Finding Keyword From Questions Keyword Suggestions For Your Website Keyword Trends