Video tests include basic video calibration, such as brightness, contrast, color, resolution, and geometry, gray scale, and overscan, as well as more advanced tests and demonstration footage designed for getting the most out either a 720p or 1080p display. Digital Video Essentials is a very comprehensive reference test disc that will enable you to get the most out of your home theater.
Very highly recommended. For a complete rundown on the disc, as well as purchasing information, go to the DVE HD Basics Webpage.
For more suggestions, check out my current list of Best Video Performance Evaluation Test Discs.