Atkins works, but it's one of the harder diets to keep following. I forget where I read this study but basically three diets were compared: Atkins, South Beach and some Low Fat diet (forget the name). All three had good weight loss (about the same over one year IIRC) but Atkins had a 50% drop-out rate after one year and the other two had about a 22% drop-out rate.
I wouldn't recommend Atkins to anyone. It works and it seems easy (eat whatever fatty low-carb foods you want, as much as you want!) but it's really not.
The best diet I've found (and helped me loose 85 lbs. in one year) is just healthy eating and regular excercise. Keep your diet around 40% protein, 40% complex carbs and 20% fat (by caloric content, not by weight) or less and excercise 3+ times a week for 30 minutes each. Eat fewer calories than you burn to loose weight or a little more to maintain your weight. Also break your meals down to 4-6 small meals a day instead of only three using smaller portions. You'll feel better, live longer, loose weight and keep it off.