Lawrence Krauss. He is very popular and on the "speaker" circuit of physicists and astronomers since he is engaging and super smart. He teaches at Arizona State U and began the Origins Project there. He often talks about how the Universe came out of Nothing, and how that can be. I would love to listen to Krauss and Hagelin talk.
Sam Harris, however, talks of his own experiences that many people would interpret as spiritual or religious - and so he would probably be on target in discussions with Hagelin. Harris's new book, Waking Up: A guide to spirituality without religion, comes out next week, and he will be in demand to discuss it. Perhaps this would be the perfect time for him to be on BatGap. Altho I have not checked, I am sure you can find Krauss all over the internet.
