You can not consider yourself a geek if you do presentations with PowerPoint! Here is a very nice alternative: S5 from Eric Meyer.
Build slideshows in XHTML and CSS and then just simply double-click on index.html in your favorite browser to start it. It includes all basic features you need to present your stuff (basic effects and navigation).
All your questions get answered at Eric’s site. Definitely check it out and never touch PowerPoint again: