DGSmith - 8:22 pm on Feb 12, 2010 (gmt 0)
A few things to keep in mind ... most tools are just estimates so youll have to take them all into consideration.
With the Google Keyword tool you MUST make sure you are set to EXACT match. This will give you a clearer expectation on what the actual numbers are (DO NOT go by broad or phrase match).
In adwords the same principle applies, to know exactly how many times a term is search (and your add appears) you must make sure its set to exact match.
There will always be difference between the Google Keyword Tool, Keyword Discovery, and any other keyword tool like Wordtracker. Just use them as estimates.