Not exactly a movie, but an anime series...
When They Cry, also known as Higurashi ni naku koro ni, is the single best anime series ive ever seen.
It has a follow-up series which is just as, if not even more, amazing as it was, called Higurashi ni naku koro ni Kai (Can be roughly translated as When They Cry, Solutions)
I also just finished the 5 episode add-on to it, called Higurashi ni naku koro ni Rei (not sure what the rei means).
I can say with 100% honesty its the single best anime series ive ever seen, possibly the single best series ive seen in general.