It becomes considerably more difficult to rapidly position the cursor when situated before an audience. It is important to think about what you will be attaching to your projector. A well labeled input panel can help cut down setup time. If your application results in a ceiling mounted projector, this is not as critical. Make sure your projector has the necessary inputs for whatever you are using during your presentation.
Most projectors allow the user to attach a monitor to the unit.
This allows the presenter to view what is being projected without having to turn their back on the audience. Keep this in mind if you plan on using an extra monitor. If you plan on presenting before a medium to large size audience, you may want a projector with a separate audio output. Having a separate audio output allows you to connect external speakers to the projector. Usually the audio system built into most LCD projectors, averages around 4 to 6 watts of power.