If you are serious about discovering the most searched words in your niche(s)
you will probably have to pay for access to a keyword database.
The most popular
commercial keyword services are Wordtracker and Keyword
Discovery
The sites below give an impression of the most popular searchterms. It's entertaining to look at but remember choosing the right keywords for your site is much more important.
Google Zeitgeist
Yahoo! Buzz Index
Lycos 50
Ask
ZDNet
Search.com

