1. Line 8-inch square pan with foil. Butter foil. Set aside.
2. Combine sugar, evaporated milk and butter in heavy medium saucepan. Cook over medium heat, stirring constantly, to a full rolling boil. Boil, stirring constantly, 5 minutes. Remove from heat; stir in marshmallows, milk chocolate chips, peanut butter chips and vanilla. Stir until marshmallows are melted. Pour into prepared pan. Refrigerate 1 hour or until firm. Cut into squares. Store tightly covered in a cool, dry place. About 1-3/4 pounds fudge.