Preheat the oven to 350°F (175°C). Grease only the bottoms of two 9x5 inch loaf pans.
In a large mixing bowl, cream together the sugar and softened butter until light and fluffy.
Beat in the eggs, one at a time, then stir in the mashed bananas, buttermilk, and vanilla extract until just combined.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing gently until just blended. Avoid overmixing.
Fold in the chocolate chips evenly through the batter.
Divide the batter evenly between the prepared loaf pans and smooth the tops.
Bake for about 1 hour and 30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the loaves to cool in the pans for 10 minutes before transferring to a wire rack to cool completely.