"Avengers" and geek-god writer Joss Whedon figured it out - the Hulk had no real character on screen previously. For 50 years in comics, the Hulk has often been a funny, touching character. The "Avengers" Hulk gives us some of that movie's funniest, and scariest, moments, and looks about as realistic as an 8-foot-tall green muscle man really could. Unlike the last two Hulk movies where the Hulk was basically a CGI Godzilla, in this one we spend enough time with Bruce Banner to truly see him within the Hulk when the moment comes.
I used to think the Hulk was a lame character when I was a young comic-collecting Marvel fanboy. The whole "Hulk smash" and Banner as whiny cursed nerd thing just seemed cliched and boring. Yet I've long since changed my mind and these days I'd rank Bruce Banner as quite possibly Lee and Kirby's second-greatest Marvel creation, just after the Fantastic Four."Hulk: Pardoned" collection, which reprints a huge swag of comics by the great Bill Mantlo from the early 1980s, which contained a story that shook up the whole "Hulk smash/Banner whine" paradigm forever. Mantlo (who was tragically brain-damaged in 1992 in an accident) might just be the most influential writer the Hulk ever had. "Hulk: Pardoned" is the start of an epic 30-issue storyline that ran from "Incredible Hulk" #270-300 or so, where for the first time Bruce Banner gains extended control of the Hulk's body and becomes "the smart Hulk."
Mantlo's writing is really underrated - it's not flashy like Alan Moore or Frank Miller were in the 1980s, so he never quite got the respect he deserved, but for mainstream superhero comics, Mantlo was one of the best at quietly filling in character and depth amongst the smashing. In "Hulk: Pardoned," we find the genius Banner dealing with the power and freedom of being in control of the Hulk for the first time, along with its pitfalls.
One of the key things Mantlo established about Bruce Banner is that the Hulk's fierce rage and animal nature isn't some "other personality" but very much Banner's dark side, the legacy of a childhood filled with abuse (a key bit of Banner's back story Mantlo also added to the character). While Ang Lee fumbled horribly trying to illustrate this sad past in his labored "Hulk" film, in "Avengers" Mark Ruffalo manages to brilliantly distill this down to just one single, crowd-pleasing line in the final confrontation scene, as he answers an earlier question about how he "lives" with the Hulk inside him:
Steve Rogers: Doc... I think now is the perfect time for you to get angry.
Bruce Banner: That's my secret, Cap. I'm always angry.
Jeff Parker's excellent "Red Hulk", which features another key supporting character becoming a 'Hulk' himself and doesn't feel like scraping the bottom of the Hulk barrel at all.
The genius with a tortured dark side isn't a new idea at all - Dr. Jekyll and Mr. Hyde are a big influence in Lee and Kirby's original "Hulk" tales. But as "Avengers" shows, the man with a raging, constraint-free id inside is still a very potent character. And the reason Ruffalo's Hulk is such a crowd-pleasing character is partly because Hulk smashing stuff up is always cool, but also because "Avengers" smartly makes Hulk a relatable hero as well, which the previous two Hulk movies never really managed to successfully do.