NEW YORK -- In a break between interviews, Iron Man director Jon Favreau argues with a comic book geek over whether it's good or bad that Marvel founder Stan Lee signed Favreau's copy of Daredevil #1.

"Somebody's written on it, it's not worth as much," the guy insists.

"I don't care," Favreau says, "I'm never selling it anyway."

The man knows his comic books. When the aforementioned fanboy pulls out an Iron Man comic book from the Demon In A Bottle series (wherein Tony Stark/Iron Man battles booze), he grabs it and knows which page to turn to.

"There's the famous image from this series of (Iron Man) smashing through a billboard hammered," he says. "The problem is, somebody else did that this summer."

That would be Hancock, the upcoming movie in which Will Smith plays a drunken superhero, who, yes, flies drunkenly through a billboard. "Hancock picked over Demon In A Bottle quite heavily," complains Favreau, who plans to explore the "drunken Iron Man" arc in an Iron Man sequel.

"The problem is there's so many superhero movies, you're walking through a minefield of what's already been done. You look at (the Batman movie) Dark Knight, which is a collection of different aspects of what Iron Man could have been -- a scientist, inventor, billionaire with no real superpowers of his own.

"So to steer clear of those things, we made Iron Man rock 'n' roll, West coast, extroverted Robert Downey Jr., as opposed to gothic, brooding and internal."

Favreau clearly enjoys talking about Iron Man -- an origin story of a military industrialist, injured in an Afghani terrorist attack, whose heart is kept beating with a magnetic chest plate (a bit of technology that becomes the centrepiece of a high-flying suit of armour).

The whole thing is a complete turnaround from '05, when Favreau made a kids' sci-fi film called Zathura. Having switched from acting (Swingers) to directing (Elf), he was pigeonholed as a comedy guy, and saw Zathura as his entry to more enjoyable work. His dream project: An adaptation of John Carter of Mars, by Tarzan creator Edgar Rice Burroughs.

Unfortunately, as good as Zathura was, nobody saw it.

"After Zathura, Paramount was presenting comedies to me because Elf was still my high water mark. But comedy's not a director's medium. I could bring comedy to everything I do, but I like to tell stories that have emotional resonance

"I said, 'What's happening with John Carter of Mars?' It was my labour of love, and ultimately Paramount, which had just greenlit Star Trek, said they didn't think it was viable commercially.

"Now Pixar's grabbed it and it's going to replace Narnia as Disney's next franchise."

But all's well that ends well in Favreau's world.

"Whatever disappointment I felt then, I'm happy now. Iron Man incorporated everything I'd done and wanted to do. It was a combination for me of Swingers -- that Vegas attitude that Tony Stark has, the anti-hero element, and the comedy I was able to play up. And as for the FX -- Zathura really prepared me for the challenges that were waiting for me on this film."

He credits his wife Joya for the pep talk that got him back in the game.

"When Zathura bombed, my wife said 'It sucks, I get it. But you couldn't ask for a better way to fail.' It could have been 'Jon Favreau sold out, he made a piece of sh-- movie, it made a lot of money, but we lost him to the dark side.' If you're going to fail, let it be commercially."

Meanwhile, Favreau is eager for a sequel. "The second ones are always better -- Spider-Man 2, X-Men 2. I think Dark Knight's going to be better (than Batman Begins), and I thought the first one was good. But the first one is always two movies sewn together -- a story and an origin story."