The two favorites in the expanded field of 10 best-picture nominees are the as-big-as-it-gets blockbuster "Avatar" and the critical darling "The Hurt Locker," which drew a tiny fraction of the audience its mammoth competitor pulled in.

Either movie would represent a first at the Oscars. James Cameron's "Avatar" would be the only science-fiction film ever to take home the best-picture prize. While war films have done well at the Oscars, Kathryn Bigelow's "The Hurt Locker" would be the first winner centered on the war on terror, a subject that has stirred little interest among movie audiences shell-shocked by news coverage of Iraq and Afghanistan.

The other eight films competing for best picture: the football drama "The Blind Side," the sci-fi thriller "District 9," the British teen tale "An Education," the World War II saga "Inglourious Basterds," the Harlem story "Precious: Based on the Novel 'Push' by Sapphire," the Jewish domestic chronicle "A Serious Man," the animated adventure "Up," and the recession-era yarn "Up in the Air."

Leaders of the Academy of Motion Picture Arts and Sciences widened the category from the usual five films to expand the range of contenders for a ceremony whose predictability had turned it into a humdrum affair for TV audiences.

Oscar ratings fell to an all-time low two years ago and rebounded just a bit last year, when the show's overseers freshened things up with lively production numbers and new ways of presenting some awards.

The overhaul continues this season with a show that farmed out time-consuming lifetime-achievement honors to a separate event last fall and hired Steve Martin and Alec Baldwin as the first dual Oscar hosts in 23 years.

"Avatar" and "The Hurt Locker" lead with nine nominations each, including director for Cameron and Bigelow, who have a personal history that spices up the competition. They were married from 1989-91.

Cameron took the directing prize at the Golden Globes, but Bigelow earned the top honor from the Directors Guild of America, whose recipient almost always wins the same award at the Oscars.

If it happens, Bigelow would be the first woman in the 82-year history of the Oscars to win best director.

Four first-time winners are expected to triumph in the acting categories.

Audience darling Sandra Bullock is the best-actress favorite for "The Blind Side," which brought her the first Oscar nomination of her career. Jeff Bridges, nominated four times previously without a win, looks like a lock for best actor for the country-music tale "Crazy Heart."

Front-runners for the supporting categories are veteran Austrian actor Christoph Waltz, who had been virtually unknown in Hollywood until his star-making turn in "Inglourious Basterds," and Mo'Nique, a performer known for lowbrow comedy who showed unsuspected dramatic depths in "Precious."