Hey, I thought this would be interesting info for people. Don't solely rely on Google Adwords: Keyword Tool. (https://adwords.google.com/select/KeywordToolExternal) I found a great keyword in the tool, 'dating advice book'. Apparently there's around 10,000 exact match searches a month.
I bought and did some promotion on datingadvicebook.org a while back.
I am now ranked #2 for the keyword, and here are my stats for last month (March 2010)
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I am quite disappointed. I would suggest using a few tools to verify the results you're looking at are accurate.
One tool I use myself to do this is SEOBook's keyword tool:
Seo Book Keyword Suggestion Tool
I hope this information saves at least one person the time and trouble I wasted on this site.