The number one story on the countdown is "The Silent Night of Batman" from Batman #219, by Mike Friedrich, Neal Adams and Dick Giordano.
Mike Friedrich was a very peace-loving guy and it certainly showed in his stories in the late 1960s. He was a sweet dude and his stories often carried with him that same sort of sweet quality.
That quality was on display in full force in this classic Batman story where a Christmas miracle takes place in Gotham City to give Batman one night off to just relax and celebrate Christmas with the Gotham City Police Department. Batman shows up and agrees to sing carols until the first crime occurs. He is shocked to see, however, that NO crimes are reported! Meanwhile, throughout Gotham, when people DO plan on committing crimes (or in the case of one young woman who thinks that her husband is dead, killing herself), they suddenly see Batman everywhere, deterring them from their crimes/suicide.
It's a beautiful story by Friedrich. Adams, for his part, was still fairly new on the Batman titles at this point, but man, did he commit to this beautifully. Sch stunning panel composition in the bold usage of the lyrics from the classic Christmas carols.
And really, what more do you want from an awesome Christmas story that Batman just rocking out with some Christmas carols with his buddies? This is a sensational Christmas story and I think it is probably the best Christmas comic book story PERIOD, let alone the best Batman Christmas story. Enjoy it in all of its awesome glory.
Have a Merry Christmas!