10) Earth-10 or Nazi Earth. I talked about this world before, so I won't spend too much time on it now. This is a world ruled by the Nazis complete with it's own Nazi version of the Justice League, the JLAxis. We've only seen this world briefly during the train wreck of a series Countdown. But I feel there's a lot of potential for great stories in this world and I hope we see more of it.
9) All Star Batman and Robin. I might be alone on this but I absolutely loved this series. I love the over the top dialogue, I loved the way the JLA was portrayed in it, I loved the more creepy serial killer take on the Joker, I just loved it from start to finish.
8) All Star Superman. There was something so special about this. Grant Morrison took the over the top, goofy, and down right stupid elements and feel of silver age Superman and made it feel so real. This book felt like modern day mythology. If you never read this, you should.
7) The Dark Knight Returns. I loved the Dark Knight Returns, I mean who didn't? There were so many interesting elements in this world. While I agree with the majority of fans that the sequel was a pretty big mess I still felt it had elements that were really interesting. I liked how Atom was kept in a petri dish and was living a barbarian's like fighting microscopic monsters. I liked how Flash was kept prisoner and forced to run to generate electricity. However flawed the execution of the Dark Knight sequel was it had some damn solid concepts.
6) Maximum's Earth. This one you might not have heard of. It was featured in a Superman/Batman story arch and featured a team of heroes called the Maximum's who were Avengers analogues. There was Viking (the Thor stand in), Soldier (Captain America), Hornet (Wasp), Monster (Hulk), Bug (Spider-man), Robot (Iron Man), and Wolfen (Wolverine). We never saw these guys again and I think it's a shame. This had the potential for so many great stories, similar to what Marvel does with it's DC stand ins, the Squadron Supreme. I for one hope we see the Maximums again.
5) Kingdom Come. What can I even say here that hasn't been said? This might be DC's most celebrated alternate universe story. The only reason this isn't higher is I just don't feel there is really much more story to be told in this universe and that's a pretty big factor for how I scored this list.
4) Earth-2. No, not that new one with the gay leather bar daddy Solomon Grundy. No I'm talking about the classic Earth 2. The original comic book universe, I had kinda hoped after Infinite Crisis when DC revived Earth 2 we would get more stories set in that world. Then New 52 happened and that hope, as well as any other hope I had regarding DC was brutally beaten to death then had it's corpse desecrated.
3) Tangent Earth. The idea behind this Earth is pretty simple. Creators took the names of DC characters and created whole new characters. Green Lantern had a mystical green lantern that could summon the dead. Flash was a female hero made of light with an array of light and energy based powers. Those were the most interesting ones to me but all and all the universe itself was pretty interesting and I hope we continue to see more of it.
2) Charlton Comics world. These heroes were originally published by the now defunct Charlton Comics. They were bought by DC and folded into the regular DC universe after Crisis on Infinite Earths. Captain Atom and Blue Beetle even became Justice Leaguers. I mentioned before what a soft spot I have for these characters, especially Blue Beetle and The Question. The Charlton Earth was restored at the end of Infinite Crisis but we never really saw much of it. I would love an ongoing series set in this world. Interesting side not in case you didn't know, the heroes from Watchmen were based on these guys.
1) The Crime Syndicate of Amerika. I did a villain spotlight on these guys before, so I won't spend too much time on them here. I'm not a fan of the pre-crisis Earth-3 version, it's the anti-matter universe version I feel is really interesting. These guys are some of my all time favorite comic book characters, there is just something about this bad ass evil absolutely gangster version of the JLA that I can't help but love.
So there you have it, my favorite DC alternate universes.