The hottest presentation tool now is Prezi, a web-based tool, which allows the viewer to zoom in and out of sections. The visuals are more of a conceptual map of the content, where the viewer or speaker can zoom around any desired topic. Because it's online, you can easily embed YouTube videos.
Take a look at this Prezi demo advocating it as a tool for teaching.
To navigate, you can click on the gray arrows at the bottom to advance forward or backward, as pre-programmed. Alternatively, you can drag the display using your mouse. Or you can zoom in/out using the + or - tools on the right.