For the past weeks I've been watching DC animated films
Batman: Under The Red Hood - one of my favorites, arguably the darkest DC animated film I've seen. I think it's pretty emotionally heavy too and you're not meant to root for Batman in this film.
Wonder Woman - pretty good and entertaining, if they're gonna make a live action film I hope they borrow elements from this one
Batman: The Dark Knight Returns I & II- I find the premise and story very interesting and I like the atmosphere. The pacing and writing is good. I just feel that Robin is a bit flat and there's so much suspension of disbelief. Gah it's a superhero film it's supposed to be.
Flashpoint Paradox - enjoyable and interesting, AU where stuff are different
Justice League:War - yeah I don't know about the comics but I enjoyed this one very much and my favorite in the JL movies, I like the different take on WW and the interactions between the heroes is fun
Superman Unbound: Average at most but entertaining
Superman/Batman Apocalypse: One of the better of the bunch and it's about Supergirl, has good action and interesting set of characters. Has Wonder Woman.
Justice League Doom: Also average, but entertaining
Justice League New Frontier: didn't finish it, you don't know here the plot was going and it's boring
Justice League Adventures Trapped in Time: written for kids who don't know better, below average and boring
Batman: Mask of the Phantasm - a true classic, a well written story with good characterization and has good music. The pacing may seem slow and the action scenes are old and unexciting though.
Batman and Mr: Freeze Sub-Zero - also one of the favorites, the film is mostly about Barbara Gordon and Mr Freeze though. It is pretty exciting and action-packed but also emotional.