Stewart picked up the Best Fantasy Actress honour at the event, held to applaud all things sci-fi, and The Twilight Saga: Eclipse was named Best Fantasy Movie. It was also a big night for True Blood, which picked up Best TV Show from number one fan Marilyn Manson.
The drama also claimed the Holy Sh--! Scene of the Year accolade for its much-publicised head-twisting sex encounter, while True Blood stars Alexander Skarsgard and Anna Paquin were named Best Horror Actor and Actress.
Other prizes went to Zombieland (Best Horror Movie), Ryan Reynolds (Top Anticipated Movie for Green Lantern), Mickey Rourke (Best Villain for Iron Man 2) and moviemaker Christopher Nolan (Most Mind-Bending Film for Inception).
Halle Berry and Megan Fox were among the early presenters but even they failed to steal the highlight of the night - as tributes to Back to The Future and Ghostbusters hit the stage.
Funnyman David Spade stepped out of Back to The Future's time-travelling DeLorean, which was driven onstage at the Greek to a standing ovation and then he introduced the film's stars Michael J. Fox and Christopher Lloyd, who were given another rapturous welcome.
Later, Bill Murray took to the stage in his Ghostbusters costume to accept Zombieland's Best Horror Movie prize.
Other highlights included a guest appearance from Sir Anthony Hopkins, who gave the audience a preview of his upcoming exorcism movie The Rite.
Horror icon Wes Craven then joined Scream 4 castmates Emma Roberts, David Arquette and Neve Campbell to present a world-premiere teaser for the latest film in the Scream franchise.
There was even a special moment for Sigourney Weaver, who was handed a lifetime achievement award and rolled onto the stage in an egg-like structure similar to the pods in Avatar.
The very special awards show was rounded off by a performance from M.I.A.