The Iron Giant
Directed by Brad Bird, who would go on to create films for Pixar, this 1999 traditionally animated film is one of the most moving ever made. The story revolves around a young boy in 1957 who befriends a giant robot that comes under government scrutiny as a result of Cold War tensions. Despite its politically charged subtext, it's a thrilling and effective movie for kids as it tells a tale of good and evil, and of love and sacrifice. Unfairly overlooked when it came out, it's gained a cult following in the past decade.