I've stopped bothering with PowerPoint for the slides I actually present. Instead, I write notes in PowerPoint (but often don't bother using them) and then draw slides which I then scan in.
I'm not an artist by any means, which forces me to keep things simple. The Eiffel tower is probably the most elaborate bit of "art" I've done. Stick people work well. As others have said, this is to support what you're saying... most of the focus should be on you, not the slides.
I've only started doing this fairly recently, but it seems to be working well so far...