Angels we have Heard on High is a favorite that hasn’t been mentioned yet.
Then there’s Christmastime is Here as sung on the Charlie Brown Christmas CD by the Vince Gueraldi Trio. In fact, that whole CD is wonderful.
Finally, I like Christmas in Prison by John Prine:
Guaraldi.
Indeed! And of course it’s really more of an Advent song – incidentally, I find it highly disappointing that the choir at my church has thus far opted not to sing it this Advent (as the musical director seems to have a marked antipathy to traditional music, unfortunately – music being the one area where I might justly be called conservative).
I like “The Coventry Carol” too, never mind that it’s a rather melancholy song about the Slaughter of the Innocents – it’s beautiful, and it’s often associated with the fifteenth-century mystery cycles, for which I have an abiding affection. I am also a great proponent of “Lo, how a rose e’er blooming” (you can hear it here under the title “Es ist ein’ Rös’ entsprungen”).
Another vote for Coventry Carol.
I’m also a big fan of Noel Nouvelet which is French for something or other.
I Don’t Remember Christmas:
I don’t remember Easter.
I do not remember fall.
So it’s possible December
Never happened after all.
Did we trim the tree together?
I can’t get the image through.
Cause I don’t remember Christmas
And I don’t remember you.
Funny, this is the same situation in my house. “Christmas Eve/Sarajevo” is my mom’s official song of the season, whereas “Star to follow” is mine.
I’m also a sucker for “O Holy Night” as well.
I also have to second the person who mentioned Vince Guaraldi. Most Christmas carols depress the hell out of me, but when I hear “Linus & Lucy” or “Skating,” I can’t help but smile. Brings back very happy childhood memories. In fact, I’m smiling right now just thinking about it. 
For sheer musical grandeur, “Carol of the Bells” by TSO always rocks the season here, but IMHO, the song that best exemplifies the meaning of the holiday is “The Christians and the Pagans” by Dar Williams.
Have always been partial to “God Rest Ye Merry Gentlemen.”
Also, the song Sting sang on one of the Very Special Christmas compilations, “Gabriel’s Message”? Amazing, haunting song.
Oh and for my favorite Christmas carol (as opposed to song) I would probably nominate “Good King Wenceslas”. I just love that song. I’m probably alone in that.
My fave traditional carol would have to be The Coventry Carol, followed closely by Une Flambeau, Jeanette Isabelle and O Holy Night. More contemporary faves would be Christmas Wrapping and Won’t Be Home for Christmas by Blink 182
Chalk me up for *O Holy Night * and Carol of the Bells, but add I Wonder As I Wander. Just a beautiful song.
But it’s not Christmas unless I hear Bob and Doug McKenzie.
Another “O Come, O Come Emmanuel” fan, here. I have a version of it that is a trumpet duet. The harmonies are so beautiful it gives me the chills.
Also a fan of “Coventry Carol,” “O Holy Night,” “God Rest Ye Merry Gentlemen,” “What Child is This?” and “Bring a Torch, Jeanette Isabella.” What can I say? I love Christmas music.
The Christmas Song sung by Nat King Cole.
We had it on vinyl when I was growing up, and now nothing in the world makes it feel more like Christmas than that song.
If I have to choose one, I suppose it’s “O Come, All Ye Faithful”. But I like many other carols such as “Hark, the Herald Angels” and “Good King Wenceslas”. To me they’re all an essential part of Christmas.
They must be sung in traditional arrangements for 4-part chorus, preferably a capella. But I do allow some exceptions, one being Joan Sutherland’s performance of “What Child Is This” in a beautiful arrangement for full orchestra.
I also like Handel’s “Messiah”. My favorite part of it for this season is “For Unto Us a Child Is Born”.
For me I always have a soft spot for Gaudete a beautiful renaissanse hymn.
I love Charo’s version of “Silent Night,” if only for the part where she tells us to “Slip in heavenly piss.”
jeanette isabella… i love the chorus on that one.
one i sing not just at christmas but anytime i’m walking along when it is snowing, esp. at night is: still, still, still.
veni, veni, is a good one.
i am also an "oh, holy night’ fan, the idea of jessica simpson singing anything, let alone my favorite christmas carol sets my teeth on edge.
my two favorite recordings of “oh, holy night” are by mahalia jackson and luciano pavarotti.
I agree with Bippy. I also rather like the Australian carol, The Three Drovers