For me, it's jingle all the way. It's got everything. A drunk reindeer. A terrorist mailman. Arnold punching a deer. Arnold punching Sinbad. Arnold punching Santa. Arnold in general.
Edit: sure are a lot of die hard fans of Die Hard.
Happiest Season felt surprisingly new as a family, love tragedy christmas movie and I really like it.
It isn't an older movie but since it came out, it is a must watch every christmas season.
Before this, it definitely was The Long Kiss Goodnight (and funny thing, the german title translates to "deadly christmas")