Someone mentioned the Dukan Diet to me recently. I checked it out, although I'm very skeptical of diets in general (especially one you have to pay for). However, I was actually impressed with Dr Dukan's diet because it makes the most sense of any diet I've heard of so far
The first phase is strictly carb free (except for oat bran - which keeps you from getting constipated) and is designed to rev up your metabolism. You're getting into the habit of walking and drinking water. Your weight should just fall off (remember we covered this concept in the series Feed Your Brain, Lose Your Belly), you should feel much better and have more energy from this stage.
Phase 2 is a low carb diet - adding veggies to the meat, cheese and eggs, walking more, still drinking the proper amount of water. His list of 100 foods should really help keep you on track. The weight should still come off fast and the oat bran you're still taking should keep you cleaned out.
Phase 3 is probably what makes the real difference and is why I think this diet is a really solid one. That phase is basically Weight Watchers.
The reason he has you do this phase is to stabilize your weight after you've lost it, so your body adapts to the new weight, helping you to stay at that weight. During this phase, he is teaching you to eat healthy.
Phase 4 (the rest of your life) you eat whatever you want (which should have changed a lot since you've followed his plan) but stay active, keep taking the oat bran and eat carb free 1 day a week.
This seems like a very good plan and is surprisingly not unreasonably priced.