I have never been into comics, and aside from Calvin and Hobbes, have never read a real comic book, so I am curious if anyone knows the timeline behind the heroes.
Thor can be considered first, since he is a God (or at least his father is alive very early on, since he was the one worshiped by the Vikings.
Captain America would be next, who came along in the 40's with Howard Stark and other scientists who started the super soldier program. At the end of the Hulk movie, Tony Stark walks into the bar and tells the general "there was a reason the super soldier program was put on ice; I personally think hardware is more reliable." This is a clear reference to Captain America. The General also responds by saying "Stark, you're always wearing such nice suites," which along with Tony's statements clearly shows that the events of Iron Man 1/2 have already taken place. The end scene in the SHIELD bunker of Iron Man 2 also has the incident on the college campus with the Hulk on one of the screens as another easter egg, showing how they interact, as well as circles on the map of the US showing the location of Captain America and Thor's Hammer.
Apparently in the Hulk some of the weapons of the Stark Industries logo on them. Someone was also telling me that the cave scene when it begins to thunder and lightening and he throws the boulder into the air, you can see Mjolinr (or whatever Thor's Hammer is called) coming down in the lightening, indicating that the events of the Hulk and Thor being banished to earth take place about the same time. The problem with this theory though is that Hulk/Banner is in Virginia, so I doubt you'd be able to see a small (relatively speaking) hammer fall from the sky all the way in New Mexico. On top of that, the Hulk had just thrown a huge boulder, so it could have just been that falling in the distance...as the saying in physics goes, "what goes up must come down" due to gravity. Some could probably debate that they (Banner and the girl) traveled all the way to New Mexico (and then make their way back to New York to see Mr. Blue), as it shows earlier in the film when he changes in Brazil he wakes up from the transformation up in Guatemala.
There are also clues in Iron Man 2 that the events of Thor being banished to earth take place at the same time, when the agent leaves Tony Stark at his house to go New Mexico and investigate the fallen hammer. This teaser scene shown in more detail at the end of the credits in Iron Man 2 is the same scene about halfway through the Thor movie.
It can probably be debated that the Hulk was actually created before the events of both Iron Man movies though. Iron Man 2 took place 6 months after Iron Man (as shown with Ivan creating his own Arc Reactor technology). The events of the Hulk movie took place during and after Iron Man 2, but flashbacks at the beginning and middle of the movie from the gamma exposure say that it took place 3-5 years earlier.
Another reference to Captain America is that same scene in Iron Man 2 when the agent is about to leave Stark at his home to New Mexico (the time Stark is creating the new element). The agent picks up disk that appears to be Captain America's shield and asks him where he gets it. It was one of Captain America's prototype sheilds I believe, and since Howard Stark played a role in his creation he probably kept one. Someone also told me it was this same material that Stark based his Iron Man suites off of (though altered the Titanium and stuff to fix the icing problem shown in Iron Man 1).
Natalie Portman's (forget her character's name) partner, the old guy, makes references to the Hulk. Apparently he was one of the guys that helped with the testing. He says somewhere in the film that he dealt with the SHIELD organization in the past, and had a friend with gamma studies that had all of his data and things taken away, as they did when they found out they had been studying the atomospheric disturbances with Thor's banishment.
It seems clear that Loki will be the bad guy in The Avengers, as shown in the scence after the credits in Thor. Apparently the ending scene with Bruce Banner has been debated to be him being controled by Loki when he is meditating into the Hulk, right before the scene with the General and Stark. So, the Hulk could be a bad guy as well, before he actually joins the Avengers. An indicator of this as well would be that same scene with the General and the Hulk. Stark says "We are putting a team together." The end of Iron Man 2 shows that the Avengers team was still in the works, with Nick Fury's "Avenger Initiative" and him still seeking after Stark. This scene in the Hulk indicates it has taken place several months after Iron Man 2 because he is clearly part of the team now. This also shows that they need his tech to help catch and stop the Hulk.
Or it could be possible that the Hulk is not controlled by Loki and they want Stark to use his tech to help recruit the Hulk who they need to defeat Loki. People have been saying that Thor probably won't come in until later in the film, which makes sense because of how powerful he is. But, Loki's powers could be far greater because of the things he learned in his time through the wormwhole to earth or with that artifact they reference at that end scene in Thor. There are also the other artifacts and relics to consider that are in that chamber in Thor, which include some gem and some gauntlet people have been talking about.
Anyway...I'm getting way into this...hehe.
