If you're an HP fan who has read the books and has been disappointed in some of the film versions (most notably HBP), then rest assured that DHp1 delivers. While it does still vary some from the written text, it does not skimp on the character development and the often glossed-over internal conflict that's usually left out of film versions. It fluctuates beautifully between laughter and despair. Also, the "kids" have definitely grown up, and it's extremely satisfying to see the chapters of the text played out on the big screen.
That said, be forewarned of three things: 1. Because of the attention paid to the finer details of the characters' emotional lives, much of this film is not "action", per se, but rather dialogue and introspection. 2. If you haven't read the book, bring along someone who has. Otherwise it might be confusing. 3. If you're thinking of bringing your kids, know that some parts of the film are exceedingly sad, and others are quite violent. There are also heavy poltical overtones (especially remisiniscent of WWII and the propoganda included therein) that most kids will completely miss. If your son or daughter is sensitive or easily disturbed by graphic images - even if they've read the book, as the visual imagery in film can really hit hard - you may want to rethink bringing them.