Cream butter and sugars until fluffy. Add baking soda and salt, then mix. Add eggs and vanilla and beat until just incorporated. Add flour and mix until well blended. Pour batter into an even layer in a greased 13 x 9 baking pan. Bake in at pre-heated 350 degree oven for about 25-30 minutes or until a toothpick inserted in the middle comes out clean (they should be a dark golden brown). As soon as they come out of the oven, sprinkle chocolate chips over top and let set for about 5 minutes. The chocolate chips should be melted and easily spreadable. Spread them in a even layer over the bars, then quickly before the chocolate sets, sprinkle on your chopped candy bars. Let cool before cutting into bars.