So it came up in the Man of Steel thread - the Detective Comics (Comics) Animated Universe.
If I was to consider this shared universe to be one show from 1992 to 2006, it would probably be my favourite show of all time. If push came to shove, then Justice League Unlimited is the one, its three seasons are incredible, the best logical progression from the Batman series.
The DCAU amounted to comics, games, movies, and TV shows. I've not seen/read/played all of them by any means, so I'll just talk about the ones that I know well, and we can all sit back and appreciate one of the greatest achievements in children's animation - and also way, way, WAY less dated than the Marvel shows from the same era, which have aged appallingly in basically every sense apart from character design. For this, we primarily have to thank Bruce Timm, but also the guys he worked with, all of whom added at least a little something to this varied, textured and deep universe.
Batman: The Animated SeriesThis is where it was all started. The original Batman series is dark, noir, edgy and iconic. They cranked out so much of this show, that some of it really, truly blows; but the good stuff is so good. This was a show that was so influential, that it managed to influence the mainstream comics. Harley Quinn was a character invented for the animated series, who carried over the comics. Mr. Freeze, on the other hand, always just an ice-themed goof in the comics, became an utterly tragic figure; the episode 'Heart Of Ice' created inside of 22 minutes a whole new character arc, a dedicated husband driven to madness and evil by his wife's neverending, living death.
Batman: The Mask Of The PhantasmThey didn't bother going back to the origin story much in the TV series, adopting the tactic I wish more modern adaptations of comics would take; it's fucking Batman, you know who he is. Instead, 'Mask' filled in the blanks in the form of a lengthy flashback early in the movie; it's a self-contained story (although it established some major lore, and the Phantasm showed up again once in JLU), even more noir than the series, with some truly stunning animation.
Superman: The Animated SeriesThis had a much more retrofuturistic feel, and simply because I prefer Batman as a character and his rogues gallery, I never liked this as much; I also didn't much care for Tim Daly as Superman as compared to the later George Newbern. It's still got a lot going for it, though; there are cameos from other heroes (Batman at one point, in a hilarious episode where Superman wears Batman's suit and beats the shit out of Bane, plus Flash and Green Lantern) as well as a lot of Superman's greatest villains like Parasite and Darkseid. For my money, it didn't really get properly good until the final season, when the universe was established and the shit could hit the fan.
Batman: The New AdventuresThe unloved runt of the Batman litter, lots of people hold this in much lower regard than the original seasons, but I actually much prefer it better; the animation is much more in the modern DCAU style and there are many great episodes; but in fairness, some of the worst ones too. The one with the mutant farm animals might have been one of the worst ever. But it also has episodes like the one explaining why Dick Grayson quit being Robin to become Nightwing, showing both the most uncompromising side of Bats, and the most caring side.
Batman and Mr. Freeze:Sub ZeroI remember this being pretty well made, but it's nowhere near as iconic as Phantasm and not particularly memorable either; it's pretty much just a long episode of the show, whereas Phantasm was a great movie in its own right, albeit a short one.
Batman BeyondOh fuck me, this is the one. This is the one. I don't see many people talk about Batman Beyond these days, but for me, this is the crowning achievement of the DCAU, because instead of adapting the existing comic storylines for the screen, but a new idea built from the ground up, with lashings of The Dark Knight Returns in it. This is set in the future, with a new character called Terry McGinnis, his father killed by Joker-inspired gangsters, taking up the mantle of Batman. There are new villains, dark, futuristic adaptations of old ones like Bane and Freeze, a whole new established universe. I treasure this show, I really do.
Batman Beyond: Return Of The JokerOften overlooked, this film is dark as FUCK. Much more young adult oriented than child oriented, it consists of the original Joker coming back from the dead in the modern times, somehow knowing everything about Bruce Wayne's life. Mark Hamill was always great as the Joker, funny, dark, cruel, lovable, but in this movie? Joker is frightening. I watch a lot of horror and it takes something special to scare me, but this Joker is probably the most terrifying version of him that existed until Ledger. He scared the everloving shit out of me, straight up murdered people onscreen, and the fate of Tim Drake is just awful. This is some dark shit, some really, really dark shit, and it's a masterpiece.
Batman: Mystery Of The BatwomanI have no idea why this even existed given that the actual Batman show had been off air for years, and it's not amazing to be honest. It has some good stuff in it, and it's entertaining, but doesn't really justify the movie runtime and the digital colouring ends up looking strangely bland and tasteless. It does, however, hint heavily at a sexual relationship between Bruce and Barbara Gordon. Now that's something interesting.
Justice LeagueThis is one hell of a show. Superman, Batman, Wonderwoman, Flash, John Stewart's Green Lantern, Hawkgirl and the Martian Manhunter all in one place. While there was a tendency at the start to nerf Superman and the emphasis on two-part episodes was a bit much, this was a dream come true for me as a youngster - this was the only show to give me that thrill of the shared universes combining that I got from Avengers Assemble. Nothing else ever gave me that same thrill. The characters were well drawn, the villains strong, the animation immaculate. And honestly, as a teenager, I learned from this show. So many great episodes. One that stands out to me is the two-parter Wild Cards, in which Joker forms a new Royal Flush gang, including a telekinetic/psychically powered Ace, and plants dozens of bombs around Las Vegas. Hamill is less dark this time, and it allows him to be fucking hilarious. Due ot the weirdly specific episode lengths required in American television, Joker says something about how the bombs will explode when the timer goes off, at which point the timer starts showing something like '44:23', and he says 'What, you expected a round number?' I also love when Batman is fighting I think, Jack(?) who has stretchy powers, and Joker throws it over to a boxing pundit, who says 'Batman has the experience edge, and weight advantage, I can't help noticing.' It's a funny, but thrilling story.
Justice League UnlimitedI give Batman Beyond the edge creatively simply for its originality, but for sheer, minute-to-minute enjoyment, this show had it all. A Justice League populated with dozens of great heroes, and less great heroes; a spotlight on Booster Gold, who's one of my very favourites. Villains from everywhere. This is a weird one because the first two seasons were a steadily building storyline that dated back to the Superman days when he fought Zod, up to the debut of Amanda Waller and her black ops goons. Lex Luthor is prominently featured too. This all culminated in a fantastic clusterfuck at the end of season two, followed by a capper episode for Batman Beyond in which an adult Terry McGinnis visits an ancient Amanda Waller, now a saved woman with no-one to talk to. Another great episode is a direct lift of a comic story, about Mongol bringing a space plant that traps you in a coma in your eternal fantasy and setting it on Superman. This one episode symbolises perfectly why I prefer Newbern to Daly, because Newbern reaches a level of rage in his voiceover work here ('Do you have any idea what you did to me?') that Daly never approached. This series also let Kevin Conroy show more of his comic timing, which can only ever be a good thing, but then even more drama too ('YOU DON'T GET TO JOKE. Not today. I just took a bullet for you.') The voiceover cast is also spectacular, Michael Rosenbaum as Flash, John C. McGinley as The Atom. The creators fully expected to be done after the first two seasons, and then they were asked to do a third, so they threw up their hands and made a fantastically cheesy season based around the old Legion Of Doom. This is way less serious a storyline (the ending is just one massive fustercluck of a scrap between basically everybody against... well I won't spoil it), and features Sonar getting to say the word 'Chickapalooza.' There's also an episode where Lex and Flash swap brains, which is hilarious because of course Rosenbaum plays Luthor in Smallville, so it is Lex Luthor playing Flash playing Lex Luthor. That episode actually has some smutty jokes in it, and my personal favourite moment in the series - Luthor realises he can find out who Flash's secret identity is, so he takes off his mask, and says 'I have no idea who this is.' I could yak on forever about this shit I really could.
Anything I've not mentioned I never saw, and obviously I missed out a ton of shit. What's your favourite parts of the DCAU? Or even any DC animations for that matter, we can push the boat out. What did you like? What didn't you like? APPRECIATE.