Weight watchers and counting calories has never worked for me. I find that the South Beach diet is what really works for me and is easy to stick to. Basically, no sugar or white flour, plenty of veggies, fruit, lean protein and low fat dairy. Any grains must be whole wheat. The reason I find this easy to stick to is because there is no counting calories or portions for the most part. Of course, common sense must prevail and eating a whole brick of cheese will not help in the weight loss process. But seriously, how much grilled chicken are you going to eat already?
Most days I forget that I am on a diet, because there is no counting. This way of eating has become my lifestyle, and I do it naturally (with the occasional cheat, of course!)