Die Hard for sure counts as a Christmas movie in our house. Lots of Christmas relevance- they plan the heist for the Christmas party specifically. He is home for Christmas. It "snows" paper at the end.
It's a Wonderful Life is very dubious, IMO. Christmas has a tiny, itty bitty part in the whole 2+ hour film. Really doesn't have anything to do with the whole movie, just shoehorned in at the end. I don't really get why it is considered such a classic Christmas movie by some- I find it long, boring, and preachy.
Love, Actually is mainly a romcom to me, with Christmas being a framing device. I don't really think of it as a Christmas film like say, Nightmare Before Christmas, Elf, or Christmas Carol. But I will watch it any time of the year- I love it.