Just curious how many adgroups per campaign you throw up to see if it works? Like they say, "throw shit at a wall and use whatever sticks." How much shit do you throw at the wall?
That was funny. I usually start out with a theme and then add more themes. Usually around 200 ad groups per campaign, 5-10 themed keywords per ad group == 2000-3000 keywords per campaign.
I should also mention that I do a lot of market and consumer behavioral research before I whip out my keyword tools.