Presentation Zen, by Garr Reynolds. New Riders Press, 2008.
Have you ever used PowerPoint(tm) templates with bullet points? I have. Garr Reynolds shows how to use strong visuals instead. The trick is to trim down to your essential story, then create a solid design using pictures, quotations, and empty space, employing various graphics principles he describes. The book was a quick read, and it definitely has helped me improve my presentations.