As for the powerpoint, that's your chance to let your personality show. My application had essays about running my own company and my values--the slides were a chance to SHOW it. I seperated my slides into professional acclaim (headshot with quotes from professional reviews of my work) , professional travel (American map with collage of pictures filling it in along with a few notable cities marked) , values (environmentalism-creative, drawn piece) , and personal (photo of my wedding and dogs).
I wanted then to get a really good feel for all of my personality. I think the most important thing is that the FEEL of the slides be really genuine. Any of your close friends should be able to look at a huge stack of slides and KnOW which one is yours. As long as it's a genuine expression of yourself, you can't go wrong. Dont get too heady about it. That's what the GMAT was for.