Welcome to PokéCommunity! Register now and join one of the best fan communities on the 'net to talk Pokémon and more! We are not affiliated with The Pokémon Company or Nintendo.
Haven't seen all of the movies, but from the ones I have watched I would say Rise of Darkrai, since it featured three of my favourite legendaries in Darkrai, Palkia and Dialga
I loved this one too, since Diancie was so sweet and cute! hardly see anyone mention it in their favorites ;_;
for me, probably Heroes, Lucario, and Spell of the Unown... though I am biased and liked most of them. Jirachi's was another great movie with a lovely soundtrack/story.