Even before I saw Avengers, the conversation I heard the most regarding the movie was all based around The Hulk and how he was a constant highlight throughout the movie. I may be biased in my thinking as Hulk is probably my #2 favorite superhero right now, but I was hoping that Marvel would ride the high of Hulk in Avengers and consider making a third Hulk movie.
Captain American 2 has been announced to the surprise of no one and it would pretty much have to take place in the modern day I would think.
There's been rumors of a Black Widow flick and after seeing Avengers, I would hope that they would base the movie off of the mission that her and Hawkeye went on in ..... somewhere that they constantly mentioned in Avengers. Through Nick Fury in there as well and it would be a more compelling movie that whatever they were going to put together with just Black Widow. Unless it was a nudy movie. I'd watch that.
I'd prefer to see the main story based on Banner's internal struggle more than a Hulk Smash villian one, but I can see why that probably wouldn't be the best and most popular choice. There are definitely villians that they could choose that would make for a compelling threat to the Hulk if done right. John Ryker, Red Hulk, Titannus, Leader, Absorbing Man. One based on Ryker or Red Hulk might feel too similar to the Norton flick though. Even Thanos, could play a part somehow to continue the set up to him vs The Avengers in the second movie.
None of these would be bad ideas. I'd dig a Red "Thunderbolt Ross" Hulk and some Hulkbusting armor that someone like Ryker comes out with for a Anti-Hulk devision of the army.
I don't think that it needs to be an origin movie at all. Yes, we don't know much about Fury, but from the roles that he has played in the Marvel movies, anyone should be able to fill in the blanks as to what kind of man he is.
Sure if you've seen the five movies that came before Avengers you'd be able to paint the entire picture, but you're not really left in the dark if you missed one, two or all of them before hand. They did a decent job about touching on any information that was required. The fact that you would have been confused says plenty about your intellectual comprehension though.