Hulk and Thor are most powerful. Thor because he is a god and Hulk because he is the Hulk. The coolest guy is Tony Stark tho because he is funny, smart and kicks butt. Captain america to me isn't as big but takes the leadership because he is supposed to represent Americas power/leadership(was kind of political when these superheroes first came out anyway).
I saw the movie this last Saturday and I think it was the best superhero movie to date. Better than Dark Night, Superman, Spider-man, and the list goes on... Other than the good action, the comedy also made it a lot better than I expected it to be.
Now about two years till the new one comes out.