Way after the Peter Jackson trilogy of The hobbit, this was one of most intense and epic moments of the book! Imagine Bard yelling at the middle of the battle:
"Arrow! Black arrow! I have saved you to the last. You have never failed me and always I have recovered you. I had you from my father and he from of old. If ever you came from the forges of the true king under the Mountain, go now and speed well!"
And then BAMMM!! Critical hit to Smaug's Heart!!