Tools for Market Research and Analysis

I came across this helpful blog post today that gave a list of 25 top market research and analysis tools as evaluated by Tino Triste in Internet Marketing. The author also provides a short description for each tool, and why it is useful. Here are a few of them. I hope you find them helpful! 43 Things
About.com: Sites A to Z
Amazon's Hot New Releases
AOL Hot Searches
eBay Pulse
eHow
Google Trends
HowStuffWorks.com
adCenter Labs: Demographic Prediction
SEOmoz Popular Searches
Yahoo! Answers
trendwatching.com
Shopping.com Consumer Demand Index After checking out the complete list at the i-com blog, are there any others that you would add? What have proven to be the most helpful market research tools that you have used?