You forgot Heroes (the 5th one) but I brought that up because that one was probably my favorite and it inspired me to make a fanfic that continues the story even further. Also, Zoroark gets a notable mention on my list.
I love them all. Because all of them have a legend in them that I like. Mostly the small ones I like most. All I've cried with. I love it when it's get very evil. And yeah I just like them all. I can't say which one is the best. The first 2 movies I saw in the movie theatre, but since then there aren't any more. Now I have watched the other 8 on Disney XD (Dutch subbed, which is crap). And the special of Mewto I got on DVD. The last 4 I've seen trough internet, animecrazy.net RULES!