Did you know that movie was a flop and not highly regarded in its day? It only became a holiday tradition, because it was so inconsequential that when a clerical error resulted in failing to renew the copyright, no one gave a damn. When the networks were looking for holiday programming, they found this film in the public domain, so they started airing it a lot around Christmastime, because the framing scenes take place on Christmas, it was made by a famous director and had a couple of big stars, and they didn't have to pay to use it. Also, any company that could afford to distribute VHS cassettes could, and often did, market it heavily as a Christmas film. It's now a traditional part of the holiday scene by virtue of innundation.

Because Die Hard is one of the greatest movies of all time, and it takes place on Christmas. And has a lot of Christmas-like themes in there as well. The underdog story, the idea of someone traveling thousands of miles to see someone because of Christmas, the redemption aspects. Even the good guy killing the bad guy boss with a weapon he had secured in a hidden place on his body was first posited in the Bible.

Christmas Vacation is the best of the movies generally accepted as Christmas fare. To this day, whenever someone uses the word "Grace" in reference to prayers before meals, I point out that she passed away fifty years ago (I know that's not the quote, but it's been more than 20 years since she passed away "30 years ago" ). Just the other day my brother mentioned that the song "Here Comes Santa Claus" makes him think of the scene with the police converging on the Griswold house.

That said, I pretty much hate cartoons and children's movies. IDK if Harry Potter is a wierd choice, because I also associate Raiders of the Lost Ark with Christmas, since I saw it all the way through for the first time on Christmas Eve one year.