The vacation planning VHS/DVD highlights the important stuff around the World including theme parks, water parks, hotels, nightlife, etc. The newest one is available for free from disneyworld.com.
DVC videos explain the Disney Vacation Club and tour the resorts and explain the DVC lifestyle. Basically, they are trying to sell you the timeshare. Newest one also available online.
Magic Kingdom Club videos (old) highlight new stuff around the World and updates to MKC benefits. I only have one of these and it is from 1991.
Souvenir Videos are just a souvenir of your trip. They aren't trying to sell you on anything.