Well, I guess I'm alone on this opinion...
My favourite song of the movie was "We Got This Together." It was the only song the Mane 6 sung together, and it really showed the personalities of the ponies. It is a great introduction to whoever has not watched FiM before. Also, my personal favourite part of this song was Twilight's solo. Her voice was just beautiful, and might be the best part of the song. Also, Twilight only sang once in the movie, and her part was amazing.