On date night with my husband last night, we saw "Elf".  I loved it!  I laughed so hard I had tears a couple of times.  I am with kids all day every day so had an appreciation of how well Will Ferrell captured the innocent weirdness of a child.  My husband didn't think it was as funny as I, but did say it was a "put a smile on your face" movie that would probably be a new classic.
If you are a sucker for the old Christmas classics like Rudolph, Frosty, and Santa Clause is Coming to Town, I think you will thoroughly enjoy this one.