Depending on what you're looking to achieve (full-screen video playback, or windowed playback), the best thing to do is use a smaller resolution with a higher bitrate. If you check out the videos my crew and I made (
http://www.moe365.org/video.php), we went with two versions. The high quality version is about 37MB. That used a variable bitrate setting in the DivX 5.0.1 codec. The low quality version is about 8MB using a set bitrate. Though these movies have a pretty low resolution, when you blow them up to full screen, you don't loose a lot quality wise. Hope this was helpful!