The science-fiction sensation "Avatar" and the war-on-terror thriller "The Hurt Locker" lead the Academy Awards with nine nominations each, including best picture and director for James Cameron and ex-wife Kathryn Bigelow.
For the first time since 1943 the Oscars feature 10 best-picture contenders instead of the usual five.
Also nominated for best-picture Tuesday: "District 9"; the animated comedy "Up"; the World War II saga "Inglourious Basterds"; the football drama "The Blind Side"; the recession tale "Up in The Air," the 1960s drama "A Serious Man," and the teen tales "An Education" and "Precious: Based on the Novel `Push' By Sapphire."
Acting nominees include the four stars who have dominated early awards shows: lead players Sandra Bullock for the football drama "The Blind Side" and Jeff Bridges for the country-music tale "Crazy Heart" and supporting performers Mo'Nique for "Precious" and Christoph Waltz for "Inglourious Basterds."
The best-picture and director categories shape up as a showdown between ex-spouses who directed films that have dominated earlier Hollywood honors.
Cameron's "Avatar" won best drama and director at the Golden Globes, while Bigelow's "The Hurt Locker" beat out Cameron at the Directors Guild of America Awards, whose recipient usually goes on to earn the best-director Oscar.
"The Hurt Locker" also beat "Avatar" for the Producers Guild of America top prize and was chosen as last year's best film by many key critics groups.
Bigelow, whose films include "Point Break" and "K19: The Widowmaker," is only the fourth woman nominated for a directing Oscar, following Sofia Coppola for 2003's "Lost in Translation," Jane Campion for 1993's "The Piano" and Lena Wertmuller for 1975's "Seven Beauties."
No woman has ever won the directing Oscar, and until Bigelow, no woman had ever won the Director's Guild honor.
Lee Daniels, who made "Precious," became only the second black filmmaker nominated for best director, after John Singleton for 1991's "Boyz N the Hood."
Also nominated for best director are Jason Reitman for "Up in the Air" and Quentin Tarantino for "Inglourious Basterds." "Up in the Air" co-writer Reitman also had a nomination for adapted screenplay, while Tarantino also earned a nomination for original screenplay.
Longtime audience darling Bullock has never been nominated for an Oscar before but is considered the best-actress front-runner, playing a wealthy woman who takes in homeless teen Michael Oher, now a star with the Baltimore Ravens.
Bullock is up against past Oscar winners Meryl Streep as chef Julia Child in "Julie & Julia" and Helen Mirren as Leo Tolstoy's bullheaded wife in "The Last Station," along with first-time nominees Carey Mulligan as a British teen involved with an older man in "An Education" and Gabourey Sidibe as a Harlem teen overcoming horrible abuse and neglect in "Precious."
Sidibe made her screen debut in "Precious," earning an Oscar nomination for her first professional acting job.
Bridges, nominated four times previously without winning an Oscar, is viewed as the man to beat this time for his role as a boozy country singer trying to clean up his act in "Crazy Heart."
Also nominated for best actor are past Oscar winners George Clooney as a frequent-flyer junkie in "Up in the Air" and Morgan Freeman as South African leader Nelson Mandela in "Invictus," Colin Firth as a grieving gay academic in "A Single Man" and Jeremy Renner as a bomb disposal expert in Iran in "The Hurt Locker."
Mo'Nique and Waltz were nominated for wicked roles, she as a reprehensible welfare mother in "Precious," he as a gleefully garrulous Nazi in "Inglourious Basterds." They were breakout roles for both, Mo'Nique leaping into the awards elite after a career of mainly lowbrow comedy, Waltz making his first Hollywood splash after working mostly in European theater and television.
Also up for supporting actress are "Up in the Air" co-stars Vera Farmiga as Clooney's frequent-flyer soul mate and Anna Kendrick as his reluctant business protege. The other nominations went to past Oscar winner Penelope Cruz as a filmmaker's needy mistress in the musical "Nine" and Maggie Gyllenhaal as a single mom involved wit Bridges' character in "Crazy Heart."
Joining Waltz in the supporting-actor lineup are Matt Damon as a South African rugby player in "Invictus," Woody Harrelson as a military man giving bad news to next of kin in "The Messenger," Christopher Plummer as aging author Tolstoy in "The Last Station" and Stanley Tucci as a serial killer in "The Lovely Bones."