Key word search SEO tool

When I not sure what search terms to bid on I use overture service. I enter a term related to my Key Word and see: related searches that include your term estimated number of times that term was searched on last month. For instance when you place a word "flash games" then you will see the next results: ... This list contain a lot of "flash", "games", "online" words. I am afraid to loose some of good words.