Just as an aside: you mention using powerpoint, and it made me wonder if you've come across, or tried out the Prezi.com cloud based presenting system yet?
I started using it about a year ago for my classes and presentations. So much easier to use than powerpoint. And all stored on the cloud, so I don't have to carry pen drives about with me - I just log in on the class computer.
Bit of a bastard if the net goes down...but much smoother experience overall and much nicer looking presentations.
Completely free to use unless you want the premium service - I've never felt the need m'self
