If you are looking for the most effective method of finding the best keywords for your web site then we recommend Nichebot. We have been using Nichebot for over a year and have found their results to be the most comprehensive and detailed. They simply blow wordtracker out of the water. So if you are looking for search engine keyword discovery then give Nichebot a try.
Nichobt offers the following services:
Keyword popularity
Adword ROI
Keyword Search Count
Daily Search Count
If you want to look at a sample click here.