My favorite Christmas movie? There are so many, how can I pick just one:

All the Rankin & Bass Classics
A Charlie Brown Christmas
How the Grinch Stole Christmas, the animated one.
White Christmas
Original Miracle on 34th Street though the remake wasn't bad either
The Polar Express
Anything Muppets ie; Muppet Christmas Carol,Muppet Family Christmas, Emmit Otter's Jugband Christmas. I know there's a new muppet Christmas movie that just got released to DVD but I haven't seen it yet.
Christmas Vacation and I could go on and on.