Using multimedia (sound, images, animation, and key text points) to enhance presentations is an obvious and strong way of getting a message across and stimulating a favourable response from an audience. And if the subject of the presentation is multimedia itself, then there is little excuse for not using the medium.
Again, multimedia authoring packages provide the means of rapidly putting together a presentation. Here is a typical multimedia configuration that I would use to present to audiences.
It consists of the following: Mac AV Computer or PC equivalent (with at least 40MB RAM, 1GB harddisc, and sound and video inputs and outputs), CD-ROM player (double-speed, multi-session, photo-CD compatable), MIDI keyboard with a simple (and cheap) MIDI control interface, small (and cheap) 4-channel sound mixer (to control sound output from the computer, CD-ROM player and MIDI player), external amplifed stereo speakers, computer input-microphone, still-video camera and video camera, display interface box (such as Videologic's Mediator) and projector or large TV monitor, or LCD viewframe and overhead 400W (min.) projector.
Note that, as the complexity of the presentation system rises, the potential for conflict between the software initialisation devices used by all those peripheral devices increases. To avoid last-minute problems, it is always prudent to test the system well in advance and in the actual presentation location. In the case of environments outside one's control, third-party guarantees that everything will arrive just before you need it for your presentation should be regarded with suspicion.
As a final rule-of-thumb, note that designing presentations for display within a 14" (640x480 pixel resolution) screen will result in fewer presentation problems that working in larger resolutions. For the moment, most projection devices will handle this resolution with little bother, but increase the resolution of the original display and you start to get into difficulties, with many devices cropping images to the lower size and losing display information in the process.