Sorry, but Christmas songs that are all white, cold and cozy fall pretty flat down here, where Christmas is sweltering, sticky and (depending on your latitude) cyclone-prone. It drives me crazy when I hear them played in the shopping centres.
I'd vote for the following list:
1. O Come all ye Faithful
2. While Shepherds watched their Flocks by Night
3. Once in Royal David's City
4. What Child is This
5. Once upon a Hillside (An Australian carol to the tune of "Waltzing Matilda")