Harold Varmus is a terrific scientist. He was awarded the 1989 Nobel Prize in Physiology or Medicine for discovery of the cellular origin of retroviral oncogenes. From 1993-1999 he was director of the National Institutes of Health, and is currently President of Memorial Sloan-Kettering Cancer Center in New York.
On top of all those accomplishments, he is a great advocate for science, and knows how to use traditional media, like TV and radio, to publicize his positions. Last night he was on the Daily Show with Jon Stewart. Here is a video clip from the show.