An excellent example of the dangers of PowerPoint presentations.
http://www.nytimes.com/2010/04/27/world/27powerpoint.html
If PPT presentations could be somehow restricted for information briefings or as illustrations for a lecture but avoided as the basis for decision making it would be a giant step forward.
PowerPoint slides discourage thought.
An excellent essay about the dangers by Thomas Hammes.
The k2p blog 