I was visiting Dan Thies' revamped SEO Research Labs site and found a couple SEO tools he linked to that may help your efforts.
The first is Peter Faber's Keyword Effectiveness Rank forumula, which allows you to either import and analyze data directly from WordTracker or, if you don't use WordTracker, to insert it yourself and receive a detailed, easy to analyze report.
Faber explains that, "in order to get an idea of the real value a keyword has for your web site you need to compare it with something. Comparing it with the average popularity and average competition of your chosen keywords will give a result that is understandable."
"The KER shows a result in percentages. A keyword with a KER of 100% is an average keyword. A keyword with a KER of 400% is a very good keyword."
So why should you use his KER system instead of Sumantra Roy's Keyword Effectiveness Index? Faber claims that KEI "assumes that the competition of a site in position 10.000.000 is just as strong as the competition of a site in the TOP10. Also it assumes that a popularity of 100.000 is twice as big as a popularity of 50.000."
Right now you can only compare 25 keywords and he says it's in testing. This service is currently free.
Another tool Dan recommended, which also comes recommended by Danny Sullivan, is Good Keywords, a free application that will help you "find the perfect set of keywords" for your website.
The software appears to be completely free and they don't even collect your email address.
Sullivan said, "I'm not easily impressed with promotion software, but this one's a keeper."
Some people are apparently using this tool to determine what products they should be selling. I haven't seen much on how it works though, or read much in forums on this one.
When you've had a chance to play with it let me know what you think.
Also, be sure to check out Dan's new ad (060204) posted on the Nigritude Ultramarine search. Smart marketing - part of his target market includes professional SEOs.