Here is a very interesting way to use flip charts. Put one on both sides of the stage and pop back and forth between them. You can have an audience member volunteer at each flip chart helping your record input from other audience members. This has a tremendous Wake em Up value because 1.) You have audience members on stage, 2.) You are in the audience, and 3.) Audience members are providing the input.
You are not limited to doing this with flip charts. You could have duel overhead projectors for larger crowds. You could still even have your darned old PowerPoint on a screen in the middle. You could even have flip charts placed all around the room so they are ready when you break up into smaller groups. Then the results pages could be torn off and taped in a row on the wall.