Dan Dennett
I would love to hear EY and DD discuss the technological singularity, and hear Dennett's opinion on the humanist response to this issue.
From the video linked to below by TimTyler, Dennett says "the idea of the singularity is possible in principle, but the idea that it is in the near future is just not plausible. I disagree with Kurzweil... "
It seems Dan has read RaymondK, but not EY. Thus a debate between Dennett and EY on the proposition: "P(smarter than human AI this century) > 5%" would be highly productive. I would expect one of EY and DD to have a major change of opinion as a result of such a debate, if it went on for long enough.
Scott Adams - http://dilbert.com/blog/
Scott is brilliant, funny, and has posted extremely original and creative ideas on his blog. But he has revealed a surprising cluelessness about matters of science and philosophy considering the amount of time he spends thinking about them. The Bloggingheads conversation can include religion, evolution, and affirmations.
I am pleased to see that many of the first names that popped into my head (e.g. Daniel Dennett, Scott Aaronson, Richard Dawkins, David Chalmers -- and of course Robin Hanson) have been mentioned.
But, surprisingly, no one's yet suggested Steven Pinker. He is one of the public faces of evolutionary psychology, and (nevertheless?) has some sympathy toward mysterianism about consciousness. (And considering that yesterday I came across an old comment by Eliezer in which he said that the English language has no rules, Pinker may be just the person he needs to talk to.)
David Chalmers has done BHtv. Maybe he could be enticed to debate whether his "Hard Problem" exists.
Robert Aumann, if it's possible to arrange.
that would be an interesting conversation.
EDIT: if nothing else, I'd like to see the discussion that arises when actually pressed on his theism. ie, I'd like to see someone ask him "I KNOW you know stuff about rationality. I know I don't need to use metaphors about mapmaking and needing to go out and look, nor do I need to introduce you to the concept if discounting the prior for a hypothesis based on its complexity, and so on, because I expect you actually really know this stuff, and know it well... So... why do you believe what you believe, especially with regards to religion?"
I'd really want to see what Robert Aumann would actually say in response to that...
Eliezer, in the ones I've seen so far I don't think you comes across very well. In particular you tend to ignore the point (or substance) of your partner's arguments which makes you look evasive or inattentive. There is also a fine line for viewers between confidence and arrogant pomposity and you often come across on the wrong side of that line. Hopefully this desire of yours to keep doing it reflects a commitment to improving, in which case keep at it. Perhaps asking a number of neutral parties about specifics would help you train for it... if you're willing to accept that you are being watched by human beings and that the audience reacts differently to different styles of presentation (it seems you do care to some extent; for example you wear clothing and appear well groomed during the conversations).
As others have suggested, trying to resolve or at least continue your debate with Robin Hanson would be interesting. A conversation with Ben Goertzel about AI safety issues and research protocols would be worthwhile to me but might not engage a broad audience. Most exciting would be Dale Carrico (http://amormundi.blogspot.com).
Dan Ariely? He is author of "Predictably Irrational" http://en.wikipedia.org/wiki/Dan_Ariely
I voted up robin hanson, but I would love either Cory Doctorow or Bruce Sterling because they are both smart scifi authors who are vocally skeptical of something like the singularity happening.
Whoever it is, in my opinion the best discussions would consist of people who share very similar worldviews yet strongly differ on some critical ideas. We don't need to see another religion debate that is for sure.
Not a very serious suggestion, but PZ Myers might be fun:
http://scienceblogs.com/pharyngula/2009/02/singularly_silly_singularity.php
http://scienceblogs.com/pharyngula/2009/02/futurists_make_me_cranky.php
Bayesian Statistician Andrew Gelman appears to have some differences with you. See: http://www.stat.columbia.edu/~cook/movabletype/archives/2009/02/different_meani.html
http://www.wjh.harvard.edu/~jgreene/GreeneWJH/Greene-Dissertation.pdf
You must debate joshua greene on the implications of moral antirealism
Andrew W.K. (musician)
He's outside of your field but is a breakout in his own field. He's open minded and sensitive to argument. But he seems to believe in some kind of weird solipsism. Talking with Andrew W.K. would let you expound upon your materialism and reductionism. You would also reach well beyond your geek readership to the armies of slightly confused, self-conscious, college educated Americans called 'hipsters'---a lot of these people are standing around waiting for the next movement to happen, and your ideas could be very seductive to them. ...
Someone with very high IQ like:
There is a list at : http://onemansblog.com/2007/11/08/the-massive-list-of-genius-people-with-the-highest-iq/
William Gibson? http://www.williamgibsonbooks.com/index.asp
He also thinks a lot - and cleverly - about the future but in a different way from Eliezer.
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 ____________."