I have several, actually. The first two Santa Clause movies are a must see, especially the second one. It's my favorite out of them all.
I also love a movie that airs called "A Chance of Snow". It's about a divorcing couple (and their kids, plus her sister) who gets stuck at the airport during a blizzard. They end up reconciling. It's so good and I finally just got it on DVD!
I also watch Rudolph every year, even though I don't like it all that much.
Borrowed Hearts is also a favorite of mine. Actually, I could go on and on about my favorite Christmas movies. There's so many good ones!