This movie, directed by Henry Selick and written by Tim Burton, is absolutely delightful. I recommend it for children, teens and adults with lots of imagination, who believe they are prepared to watch a different and sensibly darker take on Christmas.
The main premise is that, whether we know it or not, all holidays are planned in advance in diverse special towns. "The Nightmare Before Christmas" takes place in one of those towns, Halloweentown, that is the place where Halloween is planned each year. Te main responsible of that planning is Jack Skellington, also called the King of Halloween. However, not many know that Jack is bored to death of always doing the same thing. Jack knows he is missing something, but has no idea whatsoever of what that is. Of course, everything changes when Jack discovers Christmastown, the town where (of course) Christmas is planned. For Jack, Christmas is something totally new, and foreign. All the same, he falls in love with it, and has a "brilliant" idea: to kidnap Santa Claus, and to hijack Christmas.
Needless to say, things don't go smoothly, but that is a big part of the fun of watching this movie. Confusions abound when Jack and all his friends of Halloweentown try to plan Christmas for the very first time, and the result is extremely entertaining. That is specially true if you are bored of classic Christmas films that end up saying the same things all over again. This is certainly not the case in this animated film :)
All in all, I think you are highly likely to enjoy this movie. Notwithstanding that, I don't recommend "The Nightmare Before Christmas" for young children, due to the fact that some of the scenes might scare them a little. Having said that, I think that this film is a treat you are going to enjoy, and thus I highly recommend it...