Iron Man: Intro to Nick Fury,“The Avenger Initiative,” and War Machine
The Incredible Hulk: Introduce to the Super Soldier Serum aka Captain America (there is a delete scene with Steve Rogers) , and Robert Downey Jr. makes cameo appearance as Tony Stark
X-Men Origins: Wolverine: Wolverine was an Avenger
Iron Man 2: Intro to War Machine and maybe Thor
Thor: Will mostly likely introduce other Avengers.
Spider-Man 4: Spider-Man was an Avenger
The First Avenger: Captain America: Introductions and Back Story
The Avengers: I say push back to 2012 so Marvel can fit in the Ant-Man movie.
Ant-Man: Founding Member so hopefully this movie comes out before The Avengers movie. This movie would have to include the other Founding Member who happens to be Ant-Man’s wife and that is Wasp.
Black Panther: Spin off
Hawkeye: Spin off
Nick Fury: Spin off