Preheat oven to 325°. Grease loaf pan lined with foil that has also been greased. Mix 2 tablespoons sugar and 1/4 teaspoon cinnamon. Set aside. Beat butter, sugar and vanilla with mixer on High setting. Add eggs, one at a time, mixing in between each addition. Beat sour cream, baking powder, baking soda and cinnamon. Mix in flour; stir in chocolate chips. Bake for 1 hour and 10 minutes. Let cake cool in the pan on a rack for 20 minutes. Remove from pan and cool completely. Let sit 1 day.