It's almost impossible for me to answer this question. I have so many 'favourites'. But Husband and I watched 'Elf' on Friday for the first time, so I decided that the following clip, of Zooey Deschanel in that movie, singing two of my Top 10, would do nicely, thankyou very much...
And then, because for me nothing brings in Christmas like the performance The Messiah at St Martins in the Fields on Trafalgar Square, here's a flash mob performing the Hallelujah Chorus on a food court back in 2010. I think I've featured it before; I KNOW I've watched it before. But every time I do, it makes me cry. I suggest that if you're at all soppy, you have tissues handy.