I personally don't think using it to "organize" your talk is very effective, but it's great for props. How much CPU time is used in a particular part of your code? Put up a graph showing it. It gets everyone on the same page and lets them discuss it. Throw up a diagram and use a pointer to direct attention to how the different areas interact. Discussing a method of rendering surface normals in a 3D model? Put up images that compare the results side by side. I've seen it used very effectively.
If you just put up slides that show your main points, you're wasting everyone's time and attention. Take a class on giving speeches, learn how to do it right, and stop distracting your audience. The only person that needs to see your outline is you.
When I was in the Air Force, I regularly received Powerpoint attachments in my email to tell me things like "Softball game against Services Squadron on Tuesday at 5pm!" with tons of clipart and whatnot. They were always from officers. They must have a Powerpoint course at the Air Force Academy. I decided that while Powerpoint was a useful tool, officers should be banned from using it.