Believe it or not, but I'm pretty sure Mariah Carey's, "All I want for Christmas is you", is the last Christmas song to become a classic. It was written in 1994. Since that time, I don't think another song has made it into the rotation of traditional holiday songs. Yes, some performers have done wonderful covers of classic songs, but no original song has risen to the level of "Rudolph" or "Jingle Bells" like AIWFCIY has.
Strangely enough, in my brief and haphazard research, I also learned that "Santa's a Fat Bitch" is the only Insane Clown Posse song to ever be charted on the Billboard Hot 100.
The holidays really are a time of celebration.