I thought this was going to be one of thoes movies that was just a let down. The way they were showing Sasuke, I figured he was just gonna get all hyped up, and then only have a 10 second cameo at the end. However, he actually played a key part in the film, even if it wasn't until the last half-hour or so....and I don't even like Sasuke. Top that off with an actually likeable mission client with a decent story and you've got yourself a nice film. Easily the best of the Naruto films to me, right next to the second one.
Like most Miyazaki films, this one is great. The art/animation is superb, and the story is very original. A recommend this for any anime fan.
Lupin III: Castle of Cagliostro(Or however you spell it)
I'm not a big fan of Lupin III.(I think it's a great series, I just haven't read/watched it much) But I have to tell you, this film is amazing. From the story to the animation to the humor to the action to the suspense, this film is one that I will gladly watch multiple times.
There are others, but these are the few I can think of off the top of my head
The best anime movei I have ever watched must be....Saiyuki: Requiem. It is absolutely beautiful in its cinematic and the storyline is intriguing and engaging. There just enough a touch of the tragic to make it memorable, but not enough to totally break your heart like Code Geass does. If you haven't watched it, you are totally missing out!
Final Fantasy VII: Advent Children
Nausicaa of the Valley of the Wind
Howl's Moving Castle
Castle in the Sky
The Place Promised in our Early Days
Gin'iro no Kami no Agito
Piano no Mori
Sword of the Stranger
The Sky Crawlers
Break Blade Movies
Mobile Suit Gundam 00 The Movie: Awakening of the Trailblazer
Miyori no Mori