Too many to narrow down to just one, but some of my favorites are;

Silent Night
Let IT SNOW
Just about anything from Bing Crosby, Mitch Miller or Burl Ives.

Speaking of Burl Ives, does John C's face pop into your mind whenever you hear a Burl Ives song? Does to me (ans proably will to you now as well) Must be the beard or the jolly demeanor

Mike