Ahhh Freya5, Once in Royal David's City is also my favourite Christmas carol. We lived in Winchester for a while and listening to the Choristers in Winchester Cathedral sing this was just amazing.
The Power of Love - Frankie goes to Hollywood, not specifically a Christmas song, but released at Christmas so always is 'christmassy' to me.
Stop the Cavalry
Merry Christmas Everyone - upbeat and positive, although i am heartily fed up of hearing it by Christmas
Rudolf - Robbie Williams
Currently teaching my 6 year old grandson the words
Fairytale of New York.
Lots really, depends on my mood whether i listen to carols or loud and noisy.