In the past 10 years I have given plenty of presentations. Since I started, I've always used the same presentation format. Because I am getting more and more questions about this, here is some information on what I use.
The presentation tool that I use is called "pres2". Or rather, it is simply the name derived from its oroginal directory name. It is an evolution of Rasmus' original "pres" tool that he used to give PHP related presentations with. It has been used in the past by many other people as well, but as far as I know, it is now only used by Rasmus and me.
The "pres2" software is also what powers http://talks.php.net. It uses XML files stored in PHP's GIT at http://git.php.net/?p=presentations.git;a=tree. The software itself is at http://git.php.net/?p=web/pres2.git;a=tree. I have however written my own renderer that uses Zeta Components' Template component in order to make it easier for me to do something a little bit more exciting with the content (such as some effects). Sadly, this makes the slides on http://talks.php.net not render properly anymore. My version of the renderer is available through the "dericks-renderer" branch of the pres2 GIT repository: http://git.php.net/?p=web/pres2.git;a=tree;h=refs/heads/dericks-renderer;hb=refs/heads/dericks-renderer
You can obtain the software and presentations by running:git clone https://git.php.net/repository/web/pres2 cd pres2 git checkout dericks-renderer git clone https://git.php.net/repository/presentations
I have used this tool for all my 259 presentations, so I have invested a large amount of time into creating all the XML files. I mostly like it because:
It is simple
I don't need to click around to make presentations
I can version the presentations and slides through GIT/SVN
I can run PHP examples directly in the slides
And because of this, there is very little reason for me to switch to anything else.