Now, this isn't a question of what's your favorite DC film, but rather what film would you say best embodies the DC Universe in all its glory, or best represents its varied craziness, delight, drama, excitement. Granted, TV shows are better at this, but I'm looking for the one movie, live-action or animated, that you'd show a friend and say, "THIS is DC".
I'll go first: James Gunn's The Suicide Squad. It may be recent, but it perfectly captures the wide variety of genres and tones that the DC Universe balances, from the silly fun to the all-out insanity to the compelling drama to the gritty realism. It bottles them up into one film, much like how DC Comics bottles all these elements into one world, that, when you think about it, REALLY shouldn't work together, but they end up combining into something so unique that you've never seen before.
What's your pick?