Graphics/animation for presentation

Honestly most of my presentation work is done with Keynote now Thank you iPads for execs

But in answer to your questions I'd be tempted to go down the Flash route as well, though with that in mind if they want PowerPoint then I'd probably do what the client has requested even though the Flash option is far better.

I think also you need to see if this is a one of or something the client would want to reuse, a dynamic Flash animation would be killer if you have something similar I'd suggest showing it to the client then upselling it to the solution you want to do.

 

Flash is a great solution for proper animation. I second that if you can go that route

 

Create Animations in Keynote (or Powerpoint)

If you want to retain the functionality of your presentation (i.e. trigger transitions and animations by clicking or advancing and, of course, presenter's notes!) the best option would be to build the animations yourself. Both Keynote and the new version of powerpoint (don't use the mac version though, use windows on your mac if you need ppt) can do really advanced stuff with a reasonable amount of effort. Plus there is no additional learning curve for people who already are used to the software and would have to start from scratch with flash.

This is a rather prominent example I did that was animated in Keynote exclusively:
http://vimeo.com/23310187

If you on the other hand don't know your way around ppt or Keynote, just render your animations in whatever program you feel comfortable and embed them as movies in the presentation software.