I enjoyed Guy Kawasaki's speech (now available online) on the Art of Innovation. Guy is entertaining, irreverent, and insightful. Although "The Art of Innovation is a speech for any stage of company that is trying to create and marketing innovative products and services", anyone interested in innovation will profit by it.
Here is one gem: Guy's 10/20/30 rule for presentations to angel investors. 10 slides/20 minutes/30 point font. That's good advice for ANY presentation.