Looks like Marvel is going to take a little bit more time to develop their new film project which was recently revealed as being Guardians of the Galaxy. They have movie the release date back from May 16th 2012 to August 1st, 2014.
Guardians of the Galaxy hasn't been officially announced yet by the studio, but it solidly looks like that will be the big movie, which is great! I don't see the point of trying to keep it a secret anymore. I imagine the official announcement will come at Comic-Con during Marvel Studios' Iron Man 3 panel which will kick take place on July 14, 6:00pm – 7:00pm, in Hall H. So stay tuned for more details!
The other Marvel movies being released are Iron Man 3 on May 3rd, 2013, Thor 2 on November 15th, 2013 and Captain America 2 on April 4th, 2014. It does make a little more sense to space out the release dates more a bit.