The Hobbit: An Unexpected Journey - Blunt the knives, break the plates, that's what Bilbo Baggins hates by The Dwarves. The Desolation of Smaug - "I See Fire" by Ed Sheeran. The Battle of the Five Armies - "The Last Goodbye" by Billy Boyd.
Please watch this video! It's a music video of Billy Boyd singing "Last Goodbye" with video clippings from both the Hobbit and LOTR and behind the scenes clippings from both trilogies. I thank whoever made this video!