I'm with Photochick on this one. CHEESE. Full body, any flavor, cheese glorious cheese. I also will never give up plain old black coffee. The only way I'd give it up is if a world renowned Doctor told me I would die if I didn't.
Though I have given up certain foods simply because of the great mental stress and long term cravings I have if I have just one bite. All of these foods are either fried carbs or sugar filled.