Klaus is a newer one, but has joined the tradition rotation
Just finished watching Klaus with the kids 30 minutes ago (we've seen it many times before), and it's just brilliant.
The long kiss goodnight!
Jim Carey's Grinch stole Christmas - exceptionally well done
Also a big fan of Elf w/ Will Farrell
Ernest Saves Christmas
Gremlins
Krampus
A Nightmare Before Christmas
Die Hard
Muppet's Christmas Carol
National Lampoon's Christmas Vacation
A Christmas Story
Home Alone + Home Alone 2
Those have all been mainstays of some sort and we try to watch at least a couple every year we can. One of our favorites was A Christmas Story playing for 24h on TBS and we'd just "jump in" wherever it was!
Depending on mood and company, sorted from "aww" to "eww":
Love, Actually
A Nightmare Before Christmas
Die Hard
Santa's Slay
The Last Christmas in the Universe (La última navidad del universo)
Die Hard
& Die Hard 2,
Die Harder
This is my pick!