[mindcrime]

Hard to pick just one, but a couple of top choices would include:

Ben Goertzel

Joscha Bach

Michael Munger

Michael Posner

Miguel Nicolelis

Melanie Mitchell

[s1artibartfast]

I don't know the rest but +1 for munger.

They way he lay out and clearly communicate complex topics literally awe inspiring.

It is a deep pleasure to read and listen to him.