As I've worked with teachers to redesign their lecture slides and presentations, I've come to the realization that, a lot of the time, slides aren't necessary. At least, not for every point that you want to make. This idea was validated when I watched a talk given by Sir Ken Robinson at the Apple Higher Education Leadership Summit.
In his traditional conversational style, he gave an entertaining speech on the role of Information Systems in the university. He discussed the concept of creativity and how many people believe they just aren't creative. Then, he told a story about a rare season of rain in Death Valley and the flowerful spring that followed and referenced the one and only slide from his talk, which contained a photograph of Death Valley covered in wild flowers. He explained that, just as life was dormant in "Death" Valley, everyone is creative whether they have discovered their creative ability or not.
I was floored. What a way to emphasize a point. Moreover, what an incredible talk that utilized only one slide at the opportune moment.