That Christmas sequel to "Snoopy Versus the Red Baron".I grew up with "Feliz Navidad" and my father singing the Chipmunks Christmas song ("We can hardly stand the wait/Please, Christmas, don't be late!").
I've always loved the Carol of the Bells but I don't know if it's religious or not.
Actually, there are very few Christmas songs I like. I don't know why so many of them bug me, but they do. My favorite religious one is probably "Friendly Beasts" (always a sucker for animals); I was pretty annoyed when the Quaker hymnal finally came out in 1996 and left out a verse.