There are various paid versions but they are not even an option for me at the moment- costing $100's of $$ per month it would far exceed my total profits.
There are a few that I have been using in the last year:
(Note: I now ignore all the numbers with keyword tools, instead I just get a handful of phrases that I think people would be interested in and target them)
Google Adwords Keyword Tool- the numbers really confuse me
WordTracker (Free)- probably my favorite out of them all because it has 100 results
Google Search Based User Tool (SkTool)- good to find what keywords your competitors are using.
Submit Express Free Tool- pretty useless because it only has 20 results all up.
As mentioned above none compare to inventory.overture.com but having the above is better than nothing.
Anyone know of any other good ones?