Oh man...sugar was my problem! It is horrible, but it wouldn't be unusual for me to go out and buy a big bag of candy (usually non-chocolate, something like Airheads or Mike and Ikes or something) and I would eat the entire bag in a day. And since these cravings would last for a week, sometimes it was a giant bag of candy a day!
I've noticed that when I'm on birth control to regulate my cycles, the cravings are much less intense. Going through Phase 1 of South Beach has helped me too, because it seems to "break" my craving for carbs. Once I am out of Phase 1, if I have some cravings for something sweet, I'll grab some Craisins. They give me the sweetness I crave but they have enough bite I can't eat a ton of them.