I have found that http://inventory.overture.com does not contain the real phrasings of searched terms on the respective serch engines. Although overture shows you the top search word cominations, they strip a "s" off the term if its plural even if its more searched with an s on the end. Another thing i dont like about overtures data is that the words are phrased in the correct order in which they are searched in real life Overture many times alphebetizes the keywords inside the phrase and in doing so obscure which keyword you perceive you should target.
For the reasons mentioned above and others, I would recommend anyone to seek out wordtracker.com to obtain lists of keywords to compete for. WordTracker offers current up-to-date databases of searched terms as they come from the users who enter them. Unobscured by language algorithms made to increase adspending, wordtracker proves time and again to be the true source of keywords for any seo project.
For 10 bucks a day, you have access to their wealth of data which easily will export to excel for sorting.
