Move oven rack to low position so that tops of pans will be in center of oven. Heat oven to 350 degrees Fahrenheit. Grease bottoms only of 2 loaf pans.
Mix sugar and butter in a large bowl. Stir in eggs until well blended. Add bananas, buttermilk and vanilla. Beat until smooth. Stir in flour, baking soda and salt just until moistened. Stir in nuts. Pour into pans.
Bake 8 inch loaves about 1 hour until toothpick comes out clean. Cool 10 minutes. Loosin sides from pans. Remove from pans. Cool completely before slicing. Store at room temp up to 4 days.