Put the sugar, milk and margarine into a saucepan and bring to a boil. Stirring continuously, boil for 10 minutes. Place the chocolate chips, baking chocolate, vanilla and fluff into a large bowl. Pour the sugar mixture over it and stir. The heat of the sugar mixture will melt the other ingredients. Add the walnuts and pour into a greased pan. A large cookie sheet lined with foil works well. Keep in the refrigerator.