There are a few “classical classics” of the holiday season, such as Messiah and Wachet auf. For “modern classical classics” we turn to Benjamin Britten.
Ceremony of Carols is popular not only because the tunes are lovely, but because it’s written for treble choir, which usually means kids, which means lots of parents have been dragged to see this. Also, it’s accompanied by harp, so you don’t have to pay a whole orchestra. It has my seal of approval because I have a weakness for antique English texts, with their charming spellings and all.
I’d say the most-loved movement is the lullaby, Balulalow.