I like SEOMoz's new page strength tool. It's getting so much attention (and traffic) they had to take it offline, but it should be back up soon. It ranks web pages on a scale of 0-10 (sound familiar?), but it also shows all the factors that went into determining the ranking. The PageStrength score itself won't do anything other than make you feel proud if yous is high. The data it provides can be useful when used properly. There are tons of tools out there. Some are better than others, some free, some quite expensive. Bart reminded me just today about the free SEO tools on Bruce Clay's SEOToolset. Aaron Wall has some of the best free SEO tools I've seen, including backlink analyzer and the new firefox SEO extension. Speaking of tools, I met Phil Burns yesterday and he was telling me about a very interesting SEO research tool his company has developed. We're going to get together soon so he can show me how it works.
Keyword and market research are fundamental to any successful SEO initiative. With so many tools out there and so many different factors to measure and analyze, it can become very easy to collect tons of data and then not know what to do with it. Making the connection from research findings to applicable search marketing strategy is one of the keys to success in the search engines.