I'm terrible at picking favorites, but I can say that my favorite movie hands-down is Amazing Grace.
As a bit of a history buff, I love great period pieces, and Amazing Grace definitely qualifies. It is beautifully filmed, the acting is excellent, the music is lovely, and the story is amazing--and, for the most part, true!
If you haven't seen it, I strongly urge you to do so. Just writing about it makes me want to watch it again!