Here's my take on some preliminary artwork for the movie. I decided to keep ultron out of the picture and to focus on the main four. I would have loved to turn it into a Drew Struzan style poster but I'm missing informations to fill the credits. It'll probably happen down the road anyways.
FULL SIZE HERE: http://img826.imageshack.us/img826/1853/v0t9.jpg
Hulk: The Incredible Hulk game key art and Blu-Ray cover, The Avengers promotional material and Sideshow's The Avengers Hulk maquette.
Captain America: Ryan Meinerding concept art, Captain America game render, Marvel Entertainment SDCC '13 pictures.
Iron Man: Phil Saunders concept Art.
Thor: C. Wen concept art, Thor The Dark World promotional material.
Background: The Avengers promotional material.
Rain Effects: The Dark Knight Rises promotional material, splash effects courtesy of Frostbo
I hope you guys will like it.