What you really want to have a look at is PicturesToExe. Having been a beta tester for this product since before it was introduced many years ago, I can say with utmost confidence that it's the finest and least expensive presentation slideshow product available at any price.
I have about every presentation slideshow product of any quality which has been produced including some costing over $1200 (complete Vegas Video Suit). I beta tested for Photodex (Proshow) before Proshow was ever released and have used their products for years (Proshow Gold, etc.). What I'm getting at is that in the entire world of "powerful" slideshow presentation software the new PicturesToExe is simply a cut above for the photographer. Let me give you a few reasons.
First PicturesToExe (PTE) does hardware rendering. This means that in and executable format it outputs as high a resolution as your input. Some of my clients have 9 megapixel monitors (I shoot for art galleries and art clients). If you want to see what quality looks like in a slideshow, you have to see it to believe it! No other current presentation software company uses hardware rendering. This means that when they make an animated still, they render at low resolutions (usually DVD quality) of around 800x600 pixels. Then if they need to output say a 2 megapixel 1600x1200 pixel image for an executable file, they interpolate up from the rendered DVD quality to get a mediocre quality output. So for the photographer who is looking first and foremost for qualiy, PTE is the logical choice.
For many years PTE simply put out quality stills with superior transitions along with great synchronized sound as well as individual voice-over for individual slides, etc. Their text handling for captions was elementary and they didn't jump on the bandwagon for Pan, Zoom, Rotate, Scroll (Ken Burns Effects) when the rest were doing this. But a couple years ago the developers began working on an entirely new graphical engine and the realization is finally upon us.
PTE has not only Pan, Zoom, Scroll, Rotate in butter-smooth fashion, they have unlimited layers, unlimited keypoints, complete opacity control for any image on any layer or any "objects" no matter how many on a single layer. They have off-center rotation, independent XY axis manipulation, Z axis manipulation via parent/child/grandchild relationships. Incredible internal text handling, etc., etc., etc. The list is far too long to explain here.
The best thing is the price. If you purchase version 4.48 before version 5 is released (about a month from now) you get free upgrade to the standard version 5.0 and an upgrade to the deluxe version is only $20. The standard version right now is $24 for a single license. The difference between the deluxe version and standard is simply that the deluxe version has DVD authoring built in and this includes the ability to output high definition DVD.
Wnsoft, the makers of PTE have a different philosophy than most software development companies in that they freely allow all registered users to download and test their beta products. Right now beta 10 has been released. Beta 11 will follow very quickly then the final release of 5.0 in about one month from now. Even with the beta versions incredible professional slideshow presentations can easily be made.
You have a fantastic opportunity to get a product which you can be up and producing quality presentation slideshows with in a half hour. In two years you will still be learning new ways to take advantage of this great software.
If you want to see some demos, follow the link below to my website and click on the "slideshow demos" link. Click on the thumbnails to download zipped Windows executable slideshows (all software tested daily for virus, trojan, etc., and clean). Then follow the Wnsoft link and say hi on the forum where you will find dozens of helpful people who will be glad to answer any questions.
Thank you folks for your input.
@ Henry: Does Keynote work for windows as well? 'Cause I'm working with windows right now...
And as far as soundslides goes, I would like to be able to have different output formats, like wmv, avi, DVD, HD etc.
Does anyone have some sort of experience with either one of the ProShows?