The line stretched around the convention center. Storm Troopers, Flash Gordon and tiny Batmen and Spider-Men were there.

Comic-Con, the nation's largest celebration of comic books and pop culture, descended on the city Thursday. Through Sunday, superheroes will walk the streets, artists and animators will be treated like A-listers and fantasy will reign.

"It's fondly referred to as nerd prom," said Blair Butler, a comic-book expert who hosts a show on cable's G4 network. More than 100,000 are expected to attend the four-day event.

Costumes are key to the event, which features displays from toy companies (including Mattel and Hasbro), game makers (Nintendo and PlayStation) and comic-industry giants (such as Marvel and DC). All come to share their newest creations and beloved collectibles with legions of loyal fans.

Bree Bahnmiller, Kristen Perotti and Michelle Moody, all 19, started planning their 2006 Comic-Con adventure as soon as last year's convention ended.

"This is, like, our life," said Perotti, who wore an orange suit to look like a member of a Japanese band called Psycho Le Cemu.

Bahnmiller was splattered with fake blood to look like Heather, a character from "Silent Hill 3," a horror video game.

Dressing up makes the event more fun, the trio said. They have different costumes for each day of the convention.

"It's like Halloween for four days," she said.

They also come to bask in their love of anime, comic books, video games and movies.

"We like a little bit of everything," Perotti said.

More than ever, movies are making a mark on Comic-Con. Sony, Warner Bros., New Line and Universal are just a few of the Hollywood studios bringing top talent to the comic mecca, where they can speak directly to the most dedicated moviegoers.

"Our demographics show that people who come to this event see movies on opening weekend," said Comic-Con spokesman David Glanzer, a 22-year veteran of the event. "(Studios) have an opportunity to talk to the people who buy those movie tickets or who tune in every night of the week to watch those shows and get feedback."

For comic-inspired films -- like the much-anticipated "Spider-Man 3," due in 2007 -- appearing at Comic-Con is a natural fit. But even non-comic movies, like this summer's "Snakes on a Plane," stand to benefit from the fan frenzy.

"It's a great marketing tool for the studios to go down there and tout their wares to what they know is a very receptive audience," said Stuart Levine, a senior editor at the trade paper Variety. "On the bad side, if the people down there don't like what they see, it could spell bad news for the studios."

But they're clearly willing to take the gamble. Sony is bringing out "Spider-Man" director Sam Raimi, along with key members of the cast, to build early buzz for the film. "Snakes" star Samuel L. Jackson and director David Ellis will be on hand to discuss their reptile adventure. Other movies getting a first look at Comic-Con include "Ghost Rider," "The Reaping" and "Saw III."

Perotti and friends said they were most excited about seeing Tobin Bell from "Saw III."

Filmmakers have enjoyed friendly relations with the comic-book fest for 30 years, Glanzer said. It was 1976, a year before the first "Star Wars" film was released, when George Lucas brought his company, Lucasfilm, to Comic-Con to promote the franchise.

"He realized that this was a market he could tap," Glanzer said. "These people loved new information and they would talk to their friends and, way before the Internet, they could create a groundswell."

Television networks are increasingly getting in on the action, too. ABC, NBC and Fox are among those promoting new shows. Film and television workshops have also been added to the roster, Glanzer said.

"It's not just about comics anymore," he said. "It's about all things having to do with pop arts and pop culture."

And, of course, costumes.

Maureen Dawson, a 26-year-old law student from San Diego, came to Comic-Con dressed as Hermione Granger from the popular "Harry Potter" films -- for the third year in a row. She loves comics, sure, but she also attends for professional reasons.

"I'm good friends with some voice actors and I'm really trying to become their representative when I graduate next year," she said. "And you have to have imagination and creativity whereever you go."