The stunning designs you'll find via this blog post are proof that it's not PowerPoint or Keynote that are to blame for mediocre presentations, but the way they are used.
To quote the author: "There’s a certain art to putting together a solid presentation and PowerPoint and Keynote are the primary tools of the trade. The “art” comes into play when you’re trying to set yourself apart; so how you use the tools is of great importance.
Often it is the design of the presentation itself that does the trick. In an effort to help you put together a great-looking presentation, here are 28 examples of creative presentation designs using Powerpoint and Keynote." . . .