Preheat oven to 350F. Grease a 9 x 5 loaf pan and set aside.
Cream the butter and sugar until it is light and fluffy looking (or about 2 to 3 minutes on high with mixer). Add the eggs one at a time and beat well. Add the flour and other dry ingredients and mix well.
Add the mashed bananas and mix - don't worry if there are chunks of banana it works just as well. Add the vanilla, nuts and chocolate chunks. (I use semi-sweet and usually add about 3/4 of a cup but milk works too - I'd suggest though using less or it may be too sweet)
Pour the batter into the prepared pan and bake on center rack for 50 to 60 minutes, or until knife blade comes out clean. Let cool for 10 minutes in the pan before removing.