I dont' want to sound like some big nerd, but I like both of them almost equally as much because they each have their characters that are just awesome and super popular. DC has Superman and the whole Justice League, while Marvel, has Spider-man, X-men, Captain America and a lot more. If I had to choose I would probably side more with Marvel because the characters are a little bit better, and they are still making entertainment for us on the bid screen, like Spider-man, Ironman, Hulk, X-men, while the only movie that DC has released in a while is Superman returns.
I like Marvel better because they have Spider-Man the Hulk I think and they are both really great characters. They also have other really good ones to. I don't know which one superman is in I think DC but anyways Marvel is better I think.