depends what you want to do.

sounds simplistic, i know, but i've recently given up powerpoint, flash, etc.

i find that it's much easier and more dependable for me to establish what i want as images, get them into a .jpg or .bmp format, and then let advancing through a photo viewer be my presentation. don't end up with huge files ('cause each image is its own file, natch), get full screen bleeds, can set to automatic advance, can run simultaneous audio, and there's no breakdowns.

Yeah... I've always only ever made presentations in InDesign (flexibility of putting words + images), then exported to a pdf, then run it on Preview (on mac) and just advance right through. Works like a charm and I have full control over the look of the presentation. It also is much quicker for me to build something in InDesign than wrestle with crappy MS template shit.

I have the same methodology as myrium, except for that I use photoshop to design the presentation instead of working in a MS PowerPoint template. Typically I will save each slide both as a PDF, for any future revisions, and as jpeg's, so that I can insert the pre-designed slides into the MS PowerPoint presentation.

Powerpoint is ok. Just avoid all provided templates and transitions other than crossfade.

Flash takes time, and the payoff is flashy animation that is mostly just annoying. Don't use flash unless you have a really good reason to use its special capabilities.

Keynote or PDF all the way...

If you are on a mac then Keynote is fantastic.
It imports movie files easliy and reliably - unlike powerpoint which has rarely worked with movies for me.

There are a whole slew of cheesy transitions too...

Take a look at Presentation blog

It is more suited to the business and 'power speaker' world but may be relevant.

thank you for all that response....