Richard Dawkins.
I would love to hear eliezer telling RD about the rationality movement and the two of them discussing what to do about the problem of finding meaning and human fulfilment in a way which is compatible with a rationalist outlook on life.
Bloggingheads.tv can't exactly call up, say, the President of France and get him to do a diavlog, but they have some street cred with mid-rank celebrities and academics. With that in mind, how would you fill in this blank?
"I would really love to see a diavlog between Yudkowsky and ____________."