Ah, 'death by powerpoint'.
Less is more if you ask me, be it transitions, backgrounds, 'fly-ins', or just the amount of slides themselves. I recall somewhere seeing a training video about how NOT to do a powerpoint pres. It brought home to me how bad some of my own must have been when I thought the more transitions I used the better the pres. I'll try and find a link to the vid if I can find it.