It's always interesting to see what the visionaries of the technical world use for their presentations. Both Steve Jobs of Apple and James Gosling of Sun's Java fame have devised their own such programs. Jobs' was used as the basis of Keynote.
Gosling's Huckster is being made available as open source on https://huckster.dev.java.net/.
Scott McNealy of Sun once banned all use of PowerPoint at Sun, figuring that people using it spent too much time fiddling with fonts, colors, and fancy transitions. I think he's had to back down on that.
What about Linus Torvalds? Like most of us, he probably uses whatever the show wants us to use :-)
And Bill Gates? I guess he uses the latest version of PowerPoint.