The success of The Dark Knight means WB wants to do another Batman movie. But the success of Iron Man, Hulk, Spider-Man, X-Men, etc means WB has to try harder to do other movies.
The Wall Street Journal talks to Warner Bros. Pictures Group President Jeff Robinov, and he states that of 8 big summer movies planned before 2011, at least 4 of those will be DC properties. The good news is none of those is going to be Justice League. WB plans to launch individual films following the Marvel Entertainment model. From the article:
The studio is set to announce its plans for future DC movies in the next month. For now, though, it is focused on releasing four comic-book films in the next three years, including a third Batman film, a new film reintroducing Superman, and two movies focusing on other DC Comics characters. Movies featuring Green Lantern, Flash, Green Arrow, and Wonder Woman are all in active development.
Supermax, the Green Arrow prison break movie from David Goyer, is my big hope. Green Lantern and Wonder Woman are long overdue, and Flash has enormous potential for chases and special effects.