Iron Man 3 already started shooting for a Spring 2013 release. Sir Ben Kingsley seems to be the film's bad guy, playing Mandarin.

Then we will return to Asgard for Thor: The Dark World, in theaters November 8, 2013. Rumors already promised a visit to the darker sides of the god's home, which the title seems to confirm. It'll be interesting to see which role Loki gets to play here, because honestly, he was the bad guy for two, it would be much more exciting to have him play a different part in this film.

After that Captain America: The Winter Soldier will hit cinemas April 4, 2014. This title refers to a rather well known storyline from the comic series that includes the return of a well-known character. Additionally Anthony Mackie is in talks to play Falcon.

After a lot of rumors for the last few months director Edgar Wright (Shaun of the dead, Hot Fuzz) displayed test footage for Ant-Man at Comic Con, received great reactions and now gets his shot at Hank Pym, probably also sometime 2014.

The biggest surprise is probably the addition of the Guardians of the Galaxy to the Marvelverse, coming August 1, 2014.
With the announcement came the reveal of the first concept art for "Guardians of the Galaxy", which you can find behind the link below. Being entirely unfamiliar with this rather new group I looked into them a little without getting spoiled too much and it seems that they have also been known to fight Thanos, the Avengers' post credits villain. So it is safe to assume that this film will tie in with the Avengers sequel somehow.

Exciting times for fans of the Marvel films! And if they manage to keep up the high quality level of the most recent releases all I can say is: the more, the merrier.