I happen to think that TV specials like Charlie Brown's Christmas, Frosty, and How the Grinch Stole Christmas are the real "Christmas Classics." Throw in the claymation Rudolf in there as well.

I also can appreciate many of the variations on Dicken's A Christmas Carol and on the ballet/story the Nutcracker.

As movies go, I'm not sure there are any that strike me as "great" Christmas movies. My favorite would be A Christmas Story.