I go with Oprah. Oprah's influence in the Social and Economic arena moves things. Any product, fad, psychological lingo, that Oprah endorses is disseminate easily and accepted by the masses.
Condi has to play politics to get her policy across, which usually becomes watered down, and she only has 3 more years. Oprah has been doing it for 20 years, raking in Billions. Heck when Bush has to go on Oprah to campaign for Presidency, and then has to beg Oprah to go to Afghanistan, he knows where the power lie.