My favorite Xmas collection 4 years running is Sufjan Stevens' 5 disc set. Here are the last 3 years' posts:
+ That was the best Christmas album ever!
+ That was the best Christmas album ever! (again)
+ That was the best Xmas album ever! [now with songs!]
If you're at all like me, you will certainly want to buy these discs. To find out, you can stream the whole thing here: http://xmas.asthmatickitty.com/. Click on 'Musical Downloads'.
My second favorite Xmas album is 'A Charlie Brown Christmas'. I realized a couple of days ago that I hadn't listened to it yet this season, so I fixed it.
I like some of the stuff on the Aimee Mann, Sarah Maclachlan and Barenaked Ladies Xmas albums...
Another great source for Xmas music (from hipsters): http://hypem.com/search/christmas/1/
Then I needed to listen to the early Messiah stuff (OT texts). Did that Thursday night.
You might enjoy the Wartburg Choir's Xmas album: Stille Nacht.
Now I'm just listening to my 200-some Xmas tunes on random play, but I might listen to more by album.