I voted for Kingdom Come and Identity Crisis. We already kinda talked about this before, but I feel like those two could make nice, short, self contained animated features. I know Crisis on Infinite Earths is amazing, but I feel like they'd either a) change the story to make it drastically shorter or b) cut so much of the story out that it'd be totally different. They seem to like to choose stoies they can adapt in one film, rather than doing a story in a series of films, so I don't think it'd work. It'd be like how they totally ruined the Death/Return of Superman story for Superman Doomsday...Granted, I still liked the new story they created for it, but that's not the point.
-Gary