Thanks for the recommendation. I wound up powering through Worm over the course of about a week, and really enjoyed it.
You should probably be at least a little bit familiar with it? There are many minor plot elements that derive from some of the more obscure comics or from recent events in the comics. I think the story was fun even not having seen all of the particular things that are being referenced, but there's certainly a great deal of DC-specific characters, and you'll probably enjoy it more being familiar with them.
Thanks! My mental concept of them did not match their actual length. I updated the post.
I have a lot of great stories to recommend, and I tried to get a wide sampling of genres and authors. In no particular order:
Inviolate - A fiction of the DC Universe. Novel length. Complete. The base conceit is basically, "what would happen if Lex Luthor went sane?" It's a little bit like watching MoR Quirrell fight the entire DCU... with SCIENCE. The same author also writes Variant Strain, which is a Spiderman/Prototype story, novel length, ongoing. It's a very clever mix of the two source materials, and has a great deal of inside references to the Marvel universe while being mainly a retelling of a game with clever concepts and a pretty lousy plotline.
Fair Vote - A fiction of the Dresden Files, novel length. It's very interesting in that it's almost completely unrelated to any of the main characters in any of Jim Butcher's novels; everything in the book is almost entirely Original Content - which means that it's a great read both for fans of the series and for people who have never read a bit of it. The lack of connection to existing characters means that most people don't happen to stumble across this one - I think it has sixteen reviews in total, last time I checked. Definitely a fic which could use more recognition.
In Flight - A fiction of Fate Stay Night and Sekirei, novel length. Ongoing. I saw that Fate/Stay Night was mentioned in last month's thread; this is probably one of the best known fics including elements from it. Because it's a crossover fic, it does a lot of explaining setting elements, which makes it a pretty okay entry point into the series if you don't mind a few spoilers. It's action packed, and very, very funny. If you prefer a story without all the crossover and with a little less humor, you might want to try From Fake Dreams, which is a fairly well written variant of the 'time travel makes a character awesome' trope.
The Road To Cydonia A Ranma / X-COM fic. Trilogy length. Ongoing, but slow to update. Further crossovers with DCU through another author. This fic very successfully takes a very silly, heroic universe and throws it into the middle of one of the darkest tactical videogames ever written. There's a strong 'peanut butter and jelly' effect - watching the Ranma characters mature, and the X-COM universe become more epic, is very interesting. The story is also long, and crosses over with Lathis' The Titans and the Lost Boy, which is a Ranma / DCU fic. Altogether, it's probably several million words, all pretty enjoyable.
He Who Fights Monsters - a Rosario X Vampire fic. Novella length. Complete. A slightly gory deconstructionist fic of a story where the main character is a human sent to a school full of monsters. Instead of befriending them, he defends against them, with ... interesting results.
The Newest Challenger - A Street Fighter / Naruto crossover, novel length, nearly complete. The author, Kenchi, is (or claims to be) an amateur MMA fighter, which means that his hand-to-hand combat scenes are some of the most entertaining I've read anywhere. Also, the author is prolific, with about 3 to 3 and a half million words published so far. The stories are consistently funny, and action-packed; the one caveat that I would recommend is skipping any sex scenes, as they're not written to nearly the same level.