Depends on my mood

If I'm feeling laid back and sincere...
White Christmas (the version from the movie White Christmas, which is my favorite Christmas movie )
Oh Holy Night by Josh Groban
Silent Night

If I'm in a livelier mood...
Calypso Noel by Johnny Mathis (and nearly anything by Johnny Mathis)
Jingle Bell Rock
It's the Most Wonderful time of the Year

And about once a year I want to hear "I want a hippopotamus for Christmas"!!