Which Heads Should Blog?

Yesterday Mark and I recorded a dialogue for Bloggingheads.tv, which hopefully should appear tomorrow. The Bloggingheads people love science, and they are always looking for suggestions for new participants. In addition to Mark and me, we've already had Julianne appear. I can think of two other obvious ideas: JoAnne and John could discuss the LHC, and Daniel and Risa could discuss late-universe cosmology. I'll get to work on those. So -- any other ideas? Who should BH.tv have on to talk about science? They need not be bloggers, although that's always nice. They do need to be realistic -- Richard Dawkins or Steven Weinberg would be great, but they have other outlets when they want to reach a wide audience. (Although it wouldn't hurt to ask, I suppose.) Any suggestions?