In a small bowl, combine sugars and cinnamon. Cut in the butter until mixture resembles coarse crumbs. Stir in pecans; set aside. In a bowl, cream butter and sugar. Add eggs, one at a time, beating well after each addition. Combine the sour cream, pumpkin and vanilla; mix well. Combine dry ingredients; add to creamed mixture alternately with sour cream mixture. Beat on low just until blended. Spread the batter into two greased and floured 8-in. round baking pans. Sprinkle with topping. Bake at 325° for 40-50 minutes or until a toothpick inserted in the center comes out clean.