Under The Red Hood might be my favorite Batman movie ever besides the Nolan films. It nails Batman's inner psyche on how he feels about the Joker and what he wishes he could do about it. It's amazing.
I think the second best DC animated movie is the Wonder Woman one, which sold poorly, but was really well written.
Crisis on Two Earths is mostly fun if you love Batman. James Woods (not Masters) as Owlman was awesome and his interactions with Batman towards the end really hit home with me.
Public Enemies brought nothing new that JLU didn't in better doses when they were on the air. It was a watered down version of those episodes. I really loved the comic though, not the movie.