PowerPoint is a multimedia application. Use the effects, transitions, and interactivity that makes PowerPoint such a good program. In one presentation, I used progressive slides to make a pseudo-animation of an MRI going around a patient's head. It worked really well. Psychology - Fortunately, introductory psychology courses lend themselves really well to PowerPoint presentations.
Psychology is a very graphic discipline.
By that I mean in order to learn the fundamentals of psychology, you must see graphic demonstrations of the phenomena. I typically demonstrate any possible effect I can on PowerPoint. Students love the interactivity and really seem to 'get it'. Empty space - a common occurrence when designing is to place too much information on a slide so that the students cannot focus on anything in particular. It's free, it works, and your students will appreciate it.