I love Oh Come All Ye Faithful at the Midnight Service,
Yea Lord we greet thee
Born this happy morning
is the start of Christmas proper for me, sends goosebumps, I get very annoyed when it's included earlier.
It was on a starry night
When the hills were bright
reminds me of coming back from Germany on the ferry, the kids were in a corner of the bar singing their repertoire from school and came back with a load of money they'd been given!
Away in a manger, my daughter, at 3 1/2 sang this for Father Christmas, he tried to stop her but she insisted on three verses, the queue wasn't amused.