We’ve all sat through too many PowerPoint presentations that are far too long, with too many slides (usually poorly designed), and entirely too much text on them. The 10/20/30 rule is Über-elegant. A PowerPoint presentation should have no more than 10 slides, last no more than 20 minutes, and use fonts of 30 pt minimum. Guy Kawasaki expounds on the rule on his blog.
[Via A PowerPoint Blog]