Nancy Duarte's Visualizing the Presentation Ecosystem session at VizThink 2008 provided an overview of effective visual story telling for people that develop or deliver presentations.
As Duarte Designs, where Nancy is Principal, has developed presentations for Adobe, Al Gore, Cisco, Electronic Arts, Hewlett-Packard, Wells Fargo, and more her perspective on how visual thinking can exponentially increase the value and power of presentations is fascinating. As exemplified by the following diagrams:
The Presentation Ecosystem: overview of the considerations (message, delivery, visual story) within effective presentations.
An outline of Diagrams (PDF) used to capture various flows, structures, data displays, and concept illustration methodologies within presentations.