9. Jennifer Nettles and Idina Menzel
CMA Country Christmas, December 1st
What happens when you take two of the most powerful voices in contemporary music and combine them on a behemoth, cross-genre, Oscar-winning hit? You get a blow-the-roof-off performance like this one between the distaff half of Sugarland and the Tony-winning Broadway and film veteran. The fact that Nettles and Menzel were so clearly jazzed to sing "Let It Go" with one another just injected another level of joy to their harmonious and soaring take on the Disney film ballad. Any hearts frozen to the holiday season were surely thawed by this dynamite duet.