The Sword in the Stone

Sweet classic story. It has a few rater fantastic scenes, but mostly it is a bit dull.
It is in general good for kids, as the bad stuff is not that bad here, but it may be a bit too complex for the younger ones, and a bit too dull for the older ones. If they love classic Disney movies in general, this is probably going to work as well. Also this is a good way to introduce your kids to the fantasy genre at an early age.