Moving to HD is expensive. You have to buy a new TV, new DVD player, and possibly a new receiver. If you've ever wondered if HD-DVD (or BluRay) is worth it, this demo I found may be interesting. These are a series of pictures taken from the DVD and the HD-DVD or BluRay of the same movie. More than just a series of pictures, they are flash animations. You can drag a bar back and forth across the screen and see the differences. Give them a try. The differences are stark. Here are the two I recommend:
Link via the HTGuys.