I LOVE "Still, still, still." Our choir hasn't done it for awhile. Maybe I'll suggest that for next year. I also love "Es ist ein Rose entsprungen," however. I used to be able to sing it in German, but no more.
I also love "O Jesu so sweet." I've forgotten the German to that as well. That's for choir or a solo piece, in my opinion.
"12 Days of Christmas" is just silly. Supposedly it is a catechism lesson, but it's still silly.
I like "Little Drummer Boy" if a choir with a really strong bass section sings it.
We will sing "O Holy Night" this year with choir and congregation, and we will sing all three choruses. Yes, there are three choruses. We will repeat the first chorus at the end so everyone can sing along.