Hard to say, there are some "pure" Christmas-movies that I enjoy, but one of the main problems for me is that American movies tend to get a bit cheesy, especially if they are Christmas-related.
Everything ends in a sugar-sweet way, and it's usually over exaggerated like hell, normally.
Anyhow, some movies that I tend to watch around Christmas because they have that "feel":
Jingle All the Way (with Arnold) - Sure it get's over exaggerated/unrealistic near the end, but everything up until then is just hilarious. Classic Arnold!
Die Hard - Another movie I just HAVE to see around Christmas, they normally tend to show the second movie on TV around Christmas as well, if I don't remember it wrong that one takes place under snowy conditions as well (was a while since I saw it), so the follow-up works as well.
National Lampoon's Christmas Vacation - I just love these movies with Chevy Chase, the comedy itself might be very simple, but I can just laugh by seeing his facial expression when he does something lol-worthy.