Pretty good coverage of Avengers visual effects on fxguide.com. There is talk about Hulk as well, which ILM did for second time after Ang Lee`s Hulk with Eric Bana (Incredible Hulk done by Rhythm+Hues played by Edward Norton). But only this time Hulk looks like his human version. I personally think this helped a lot to keep connection with original actor and audience as well. There are also more shots with this creature in-between fights. He gets enough screen time to show off properly.