Primer for The Avengers

The release of Marvel's big crossover film, The Avengers, is coming out this week.  Now, despite what AMC Theaters would have you to believe, there is a chronological viewer order that differs from the release order.  This post lists the Marvel films in that order, with all information needed to watch The Avengers.  

REVISED ON 06/15/13
Iron Man
Why Is It First? It takes place before Iron Man 2. 
New Characters
Tony Stark a.k.a. Iron Man
Pepper Potts
Nick Fury
Agent Phil Coulson
What Important Happens: Genius billionaire Tony Stark (son of Howard Stark) creates a highly advanced battle armor to help defend America from its enemies.  He eventually reveals his identity to the world.  Samuel Jackson identifies himself as Nick Fury, director of Strategic Homeland Intervention and Enforcement, Logistics Division (S.H.I.E.LD.) and approaches Stark about the "Avengers Initiative".  He also implies the existence of Captain America and/or The Hulk.  
Rating: A-
This has a very straight forward superhero origin story, broken into three acts.  As a film that takes place in the technology obsessed twenty-first century, the suit and other gadgets do not feel out of place.  Robert Downey Jr. and Jeff Bridges both give great performances as well.  The comic book elements are pretty light so it's a good gradual start to the series.

Iron Man 2
Why Is It Second? It's after Iron Man, and the post-credit scene puts it right before Thor, with some crossover.  
New Characters
Agent Natasha Romanoff
What Important Happens: James Rhodes (now played by Don Cheadle) steals a prototype of the Iron Man armor and has it enhanced with more weapons, becoming the armored superhero, War Machine.  Fury plants Natasha Romanoff to spy on and assess Stark.  Based on her report, Fury decides Stark would not be a good fit for the Avengers team, but brings him on as a consultant.  Agent Coulson heads into the desert to check out a mysterious large hammer embedded in the ground. 
Rating: B+
The film is a bit of a step down for most fans, mostly because Stark spends most of the film being very anti-heroic.  The action is still very good and Mickey Rourke gives an awesome performance as the villain, Ivan Vanko.  

A Funny Thing Happened on the Way to Thor's Hammer
This a short that features Agent Coulson on his way to the hammer at the end of Iron Man 2.  It's a one-off story with no extra developments to the larger story.  You can watch it here. 

Thor 
Why Is It Third? Because it takes place after Iron Man 2 and the post-credit scene sets up Captain America: The First Avenger.
New Characters
Thor 
Loki
Dr. Erik Selvig
Clint Barton a.k.a. Hawkeye
What Important Happens: On the planet Asgard, Prince Thor is robbed of his powers and exiled to Earth by his father for being an arrogant jerk.  His hammer is sent separately and he can't use it until he proves himself worthy.  He is taken in by Dr. Selvig and his staff while he tries to recover the hammer, which is guarded by S.H.I.E.L.D. agents.  His brother Loki tries to take over Asgard and kill Thor, but Thor learns humility from Selvig's assistant, Jane, gets his hammer back and foils Loki's plans.  Unfortunately, transport with Earth is severed and Loki escapes.  Fury recruits Dr. Selvig to study a strange energy cube and it's revealed that Loki is possessing Selvig and has an interest in it. 
Rating: B
The movie isn't as action driven as its predecessors.  Most of the film is a fish-out-of-water story about Thor living on Earth without his powers; it's appropriately funny.  Most of the issues in the film are in the performances.  Natalie Portman gives a rather wooden performance and has poor chemistry with Hemsworth.  

Captain America: The First Avenger
Why Is It Fourth? It has to go after Thor to make sense. 
New Characters
Steve Rogers a.k.a. Captain America
What Important Happens: Steve Rogers is transformed into the world's first superhero via an artificial serum to be a new super-soldier to fight in WWII.  Afterwards, the lead scientist is killed before the process can be repeated.   Rogers, now called Captain America, battles a Nazi super villain called the Red Skull over control of a cube-shaped alien power source called the Terrasact.  Rogers succeeds and the cube is recovered, but he ends up frozen in the Arctic.  He is thawed out 78 years later and greeted by an unnamed Samuel Jackson character, who works for the government.  
Rating: C
The film has many story problems, especially in the third act.  Also, the excessive advanced technology and special effects makes the film look like a high budget B movie.  

The Incredible Hulk
Why Is It Last? It runs parallel to Iron Man 2 and Thor, but the climax and final scenes are all after those films. 
New Characters
Bruce Banner a.k.a. The Hulk
What Important Happens: While trying to recreate the formula that made Captain America, Dr. Banner turns himself into a green rage monster.  He goes into hiding to try to find a cure.  General Ross, who was in charge of the project, eventually catches him, but one of his men, Blonski, takes the serum and turns himself into another Hulk.  Banner subdues him and escapes again.  He then starts practicing control over his power.  Stark approaches a defeated Ross about "putting a team together." 
Rating: B
The film is a fugitive story in the superhero genre.  Any scenes without the Hulk are supplemented by scenes of Banner on the run from Ross's forces.  The film has the advantage of the origin story happening off screen, so the character relationships are already established and the story hits the ground running.  The story also examines the perils of superpowers rather than the benefits. A major drawback is Liv Tyler's excessively shrill performance.

The Consultant
This is another short starring Agent Coulson, though it has a little more to it.  The World Security Council wants Blonski on the Avengers team, but Fury and Coulson don't, and Blonski is in the custody of General Ross.  Coulson sends "the Consultant" to ask for Blonski's release (putting the conversation between Ross and Stark into context).  Ross refuses Stark's request and Blonski is kept off the team.  Watch here.

It's time.  Avengers assemble!