Put all ingredients into blender container. Cover and process on high speed until smooth.
Chocolate: Omit vanilla. Add 2 tablespoons chocolate flavored syrup.
Tropical: Omit vanilla. Reduce milk to 1/2 cup. Add 1 can (8 ounces) juice pack crushed pineapple and 2 tablespoons cream of coconut.
Strawberry: Omit vanilla. Increase milk to 1 1/4 cups. Add 1 package (10 ounces) frozen strawberries, slightly thawed.