Hey there! I came across this contest, and since I love both Marvel and Lego I could not just move on. Moreover, when will I have again the chance to recast The Avengers? So let's get started.
Emma Stone - Black Widow/Natasha Romanoff
She definitely has the potential. She helped Spiderman save the world not once but twice, and remember Zombieland? She did great with those zombies. Also, she is gorgeous, she is a redhead already and nobody will ever suspect she is a spy.
Ryan McPartlin - Captain America/Steve Rogers
Mostly known for playing Dr. Devon Woodcomb on Chuck, McPartlin would make a perfect Captain America. He's got the body, and most important he looks like the guy who'd do anything to save the world.
Daniel Craig - Hawkeye/Clint Barton
I couldn't think of a better Hawkeye than Jeremy Renner, but since I can't have him I'm having Daniel Craig. He does basically everything as James Bond. I don't think using bow and arrow instead of guns will be a problem for the guy.
Zachary Quinto - Hulk/Bruce Banner
He has already conquered nerds' heart - including mine - by playing Spock in the Star Trek remakes and a psychopath, also known as Sylar, in the Sci-Fi TV series Heroes. He can definitely pull off an angrier Bruce Banner than Ruffalo.
Chris Pine - Iron Man/Tony Stark
He has already worked with Zachary Quinto/Hypothetical Hulk more than once, he has the look and the charisma to pull off such a character. Also, the ladies love him, and that is one of Tony Stark's main features.
Charlie Hunnam - Thor
Chris Hemsworth makes a perfect Thor already, but this British man would totally rock the God of Thunder. Just put together the strength and the will of Pete from Hooligans, the Mjölnir and a red mantle and there you have!