Marvel was really the first to do a lot of things, like give characters regular, average joe problems, making the identity of a superhero (4 super heroes, in fact) public knowledge, and also the first to have real teamwork, not just batman and robin style "Hand my my batarang, boy wonder!" shit.
Also, I find Marvels reccurring characters more endeering. Superman is an overrated bitch of a character, far too straightforward and generic. The only reason he is so popular is that he was the first real comic book superhero.
Now, DC has a few characters that have really evolved and matured, namely Batman, and they also have published some of the best graphic novels and anarchic comic book series in history. For instance, V for Vendetta, Hellblazer, and The League of Extraordinary Gentlemen are some of the best comiics/graphic novels i've read in ages.
Your list is missing one other major key player, though: Image. Image published Sin City, 300, The Walking Dead, Spawn, and several other incredible graphic novels and comic books. They may not have the fame and fortune of Marvel and DC, but they're still big.
