It's the Alistair Simm Christmas Carol for me too, but someone above mentioned A Child's Christmas in Wales and that would be a close second. It was one of the last performances for Denholm Elliott, and he's great as the grandfather who rediscovers the magic of Christmas through the bedtime story he tells his grandson. Two scenes stand out in my mind. The boys decide to carol at a "haunted house" and are half way through God Rest Ye Merry Gentlemen" when a noise behind the door scares them away. Then we hear a weak, elderly voice continuing the song from behind the door. The scene where the whole family sings "All Through the Night" is also touching.