In a video interview with Bloomberg earlier today, Marvel Studios President Kevin Feige said that the studio plans to make two movies a year for the foreseeable future, and that shortly after Captain America begins filming they will start shooting a pair of films which have yet to be announced.
"We want to do two films a year," said Feige. "Avengers is our only film this year, but in a week and a half we begin filming Iron Man 3. By the end of the summer we'll be working on the next Thor film, early next year the next Captain America film. Those are the three we've announced so far; we've got two beyond that that we haven't announced yet, but we're working on."
Top candidates for that are the often-teased Ant-Man and Doctor Strange films, Guardians of the Galaxy, The Incredible Hulk or the already-announced Avengers 2. At least one of those (Avengers 2 notwithstanding) might turn out to be a feature-length animated film from Disney.