I've tried the Natalie Cassidy one which was pretty good as an overall workout, and I think a lot of the more recent dancing ones are good as it's less like hard work because it's fun, so you're more likely to stick with it! Maybe rent out a few to try them before you buy, or vary it so that you keep yourself interested. Also if you're looking for cheap ways to keep fit at home, you could buy a hula hoop as that's a new craze which definitely works out the tummy as well as working up a sweat!
I know it's not strictly a dvd but if you have a Wii I wholeheartedly recommend the 'EA active game'. Aside from coming complete with a band for muscle resistance training, it includes full body workouts you can costumize, a 30 day challenge to fire up your fitness, an easy way to monitor your water and food intake and your diet. It's a really good 30 minutes workout that doesn't get dull and manages to work all muscle groups while making you sweat.
There are so many exercise dvd out that promise results. But the best way to find a good one is to find what exercise sorts your body. Go to several classes ,talk to the trainers, talk to others in the classes, find out how long they have been there. If they have been coming for a long time it means that they enjoy the class.When you find what is best for you then buy your dvd, use this as well as classes for better results , as you can always ask for help from the trainer if your not seeing results, hope this helps. Good luck in your training