Awright, here are some quick suggestions.

Handel, Messiah -- I know, I know, you already have it, but how can you discuss “holiday” music without mentioning the Messiah? Without going on at tedious length, my favorites remain Pinnock (DG) and the politically incorrect Beecham/Goosens (RCA). I have not heard a lot of the newer stuff (e.g., McCreesh, Christie, Suzuki. I’d be interested in hearing what others think of these versions.

Bach -- Although I do like and play the Christmas Oratorio (generally Gardiner, DG), if I want Bach around the holidays, I tend to pick out cantatas, even though they may not be season-specific, and in particular cantatas from the complete 1970’s Harnoncourt /Leonhardt series (Teldec). These versions are admittedly an acquired taste, but I love them. Both the instruments and vocals are sometimes a bit rough, but Harnoncourt uses boys for the soprano parts (as Bach would have) and the effect is wonderful. The discs are sold these days (I believe) only in 6-disc boxes. If you were to spring for one box, I would suggest the third volume (Cantatas 37-60), which includes soprano solos by Peter Jelosits [I may be misspelling the name].

“A Venetian Christmas” – Paul McCreesh, Gabrieli Consort (DG). This disc, featuring music by Giovanni Gabrielli (and others), recreates a Christmas Mass in St. Mark’s in Venice circa 1600. I have not heard a bad disc by McCreesh.

“Lutheran Mass for Christmas Morning” – Another Paul McCreesh project (DG), this disc features music by Michael Praetorius to recreate a German Christmas mass circa 1620.

“On Yoolis Night”, Anonymous Four – You may have this one; it garnered much praise when it came out, all deserved. Four women singing motets and songs a capella. Gorgeous and hypnotic.

Messiaen – 20 Regards sur l’Enfant Jesus (Austbo, Naxos) – At Naxos prices, you get a fantastic recording of one of the great piano works of the 20th Century. [Not Christmas music, but if you like this, get Austbo’s other Messiaen piano works on Naxos.]

“A Gift for You from Phil Spector” – I got this disc as part of the 4-disc Phil Spector “Back to Mono” box, but it seems to be available separately. Darlene Love, the Ronettes, et al., singing “White Christmas”, “Frosty the Snowman”, “Santa Claus is Coming to Town”, etc. complete with that wonderful “wall of sound”.

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My all-time favorite (if I can even talk about favorites
of Christmas music) is the The Swingle Singers Christmas
album. It's a perennial favorite and is always in print,
but maybe not at the Best Buy... more likely Barnes and Noble
or Media Play.

My personal (maybe all-time) favorite though was originally
from the movie Holiday Inn. It's sung by Bing Crosby and
the title is "Count Your Blessings" done in the Thanksgiving
segment of the film. But wait, there's more. The version
I think that is the best is done by a piano trio led by Tashiko
Akiyoshi. It is an up tempo "Count Your Blessings" rendered
in the style of Eddy Duchin.

Tashiko Akyoshi and Lou Tabakin have a big band as well.

That title from Anonymous Four from above sounds interesting
to me. Wisht I had access to it.