Right now, the Bells of Dublin Christmas CD by The Chieftans and a bunch of carols by the King's College Choir, Chanticleer and the Cambridge Choir. I have spent hours putting together mix cds of Christmas music for presents to family, friends, my kids' teachers, our priest, etc...
Someone is going to howl, but you just can't beat English boys choirs and Irish music for Christmas. Even the most cheerful and upbeat Greek chant (is there any?) just isn't the same for Christmas. For the fun Christmas cd I went with Charlie Brown Christmas, The Drifters, Big Bad Voodoo Daddy (you never heard Jingle Bells like this before), Bing Crosby, Raffi and The Chieftans again.