A Christmas Carol - Dickens
The Dead - James Joyce (not exactly uplifting, but deeply touching)
A Child's Christmas in Wales - Dylan Thomas
The Christmas chapter in Anne of Green Gables when Matthew gives Anne a dress with puffed sleeves.
Alistair Macleod has a beautiful Christmas short story, I can't recall the title, but it's in his compilation Island. I can't look it up because I loaned it to someone who never gave it back. I don't even blame them too much, because it's a wonderful book of short stories and I wouldn't want to give it back either. ETA: Found it - http://www.amazon.com/Every-Thing-There-Season-Christmas/dp/077105565X/ref=sr_1_4?s=books&ie=UTF8&qid=1289843317&sr=1-4
How the Grinch Stole Christmas
The Night Before Christmas
Jan Brett - DD loved Annie and the Wild Animals, but The Hat and The Mitten are charming and she has Christmas themed books as well.
Robert Sabuda's Winter pop-up book
Stranger in the Woods - the picture book by Carl Sams and Jean Stoick