Weightwatchers points system is good.
I lost 2 stone a few years ago and only put it back on when I had ds, I am losing weight at the moment and I am nearly back to my goal weight of 7.9. For me the only way that works is to lose weight very slowly, I only average about 1lb per week but it does stay off. In the week, I eat very sensibly - smoothie for breakfast, ryvitas or jacket with low fat soft cheese for lunch and chicken or fish with vegetables for dinner, I only eat carbs after 7.00 pm on one night of the week. I do usually have a glass of wine most nights. At the weekend I eat whatever I want, I eat out a fair bit mainly thai or italian and I cook that sort of thing as well. I always have a bar of chocolate every Friday & Saturday, and 1/2 bottle of wine on weekend nights. The only thing I am strict on is desserts, I hardly ever have them as they are loaded with calories. When I reach my goal weight I will increase the amount of carbs that I eat in the week. IMO the only diets that work are the diets that you stay on therefore don't be too strict as it is difficult to stay motivated.