nadja's version of god rest ye merry gentlemen is my favourite.
i am the wooden doors that contain the black wizard (that are) wolves in the throne room (of magick)
but also don't forget:
TSO (already mentioned)
Joe Pesci - If It Doesn't Snow On Christmas
ELP - I Believe In Father Christmas
Elton John - Step Into Christmas
The Waitresses - Christmas Wrapping
Moody Blues - the December album, and What Child Is This?
Elvin Bishop - Silent Night
Billy Squier - Christmas Is the Time to Say I Love You
Bob Seger - Sock It to Me Santa
Twisted Sister - A Twisted Christmas album