Greg Graffin is most noted as the lead singer of punk rock band Bad Religion.
He also has a Ph.D in Zoology and teaches paleontology at UCLA. The Ph.D. dissertation was officially a zoology Ph.D., supervised by William B. Provine at Cornell. The dissertation was entitled "Monism, Atheism and the Naturalist Worldview: Perspectives from Evolutionary Biology."
Some other notable things:
Greg Graffin received the Harvard Secular Society's "Outstanding Lifetime Achievement Award in Cultural Humanism" on April 26, 2008
He has written many papers and projects on the subject of Evolution vs Religion, and led a major study/project titled "Cornell Evolution Project" Which included the participation of many big name evolutionists such as Richard Dawkinshttp://www.cornellevolutionproject.org/
Here is his wikipedia:http://en.wikipedia.org/wiki/Greg_Graffin
I believe Graffin is an easily accessible quasi-famous propanent of evolutionary theory and would be an interesting new twist on the guest interviews that include mostly scientists.