It really depends on what *you* like. Technically anything that gets you moving and keeps you interested will help get the weight off, but if you don't like the workout, you won't stick with it. You might check your local video store and try a few before committing to one program. I recommend any of the Tae Bo series, something like Pilates or yoga for low impact, or any of the various aerobic workouts for cardio.
Keep in mind that you *must* address your diet if you want to get and keep the fat off your body. Exercise is great, but it's a small part of the equation. All the exercise in the world won't make up for a bad diet. Fix both parts, and you'll be lean and healthy for life.