General Stanley McChrystal and others decry the poor use of PowerPoint: We have met the enemy and he is PowerPoint!
Likewise Seth Godin here.
How many mind-numbing presentations/talks/sermons have we all sat through, or given, where PowerPoint is being over-used, the speakers turns his/her back to us and reads the bullet points off the screen, etc?! Some good tips and the worse errors to avoid here.
Great stand-up comedy about Powerpoint here!