Indeed you do.
I personally couldn't recommend the movie enough, since it's my absolute favorite anime and, by extension, my favorite movie. Of course, for expectation reasons I won't say much, but I will say that you should consider watching the dub if you do. I haven't watched the Japanese version, myself, but I don't think there's anywhere else in anime that you can find an English cast as all-star as the one for this movie, there are fantastic VAs everywhere and it's actually quite terrifying.
But, eh...just watch it. It's great. Please, watch it. Seriously. Do it.