"We've done an amazing job at keeping things fresh," Tobey Maguire tells USA TODAY. But, he adds, "it's hard to imagine continuously coming up with stories that deserve to be told. I'm not sure if there are more stories for this character that are interesting enough to be excited about doing more."
Sony Pictures, the distributor for the films, isn't saying either way. And superhero franchises, such as the Hulk, have been pronounced dead, only to resurface under a new director or production company.
But Spider-Man producers concede they haven't looked beyond this installment of the series, which they always viewed as a trilogy.
"We don't have a book we're adapting, like a Lord of the Rings," says Spider-Man producer Laura Ziskin. "It's open-ended. But this could be the last. We've never started on the next movie while we were working on the current one."
More than a dozen big-studio movies will be featured at the nation's largest comic-book convention this weekend, but none come shouldering more excitement or expectations than Spider-Man. It's due in theaters May 4.
Producers - and perhaps, they say, a star from the movie - will unveil some hastily gathered footage from the film Saturday as a goodwill gesture to the convention, which has been a taproot of the franchise's loyal following.
"This is a going-home kind of thing," producer Avi Arad says. "We brought the first one here and the fans have supported us and (director) Sam Raimi from the start. We wanted to say thank you."
Filmmakers are closely guarding plot points to the film, though it will feature a new villain, Sandman, played by Thomas Haden Church.
And Ziskin promises one foe will be Spidey himself.
"He'll have to battle villains within," she says. "I love what we've done with this character."
So does Maguire.
"This one, to me, has more interesting twists and turns" than the first two, he says. "It's been a fun ride."