In a year when best picture nominees thrived on controversy, the Academy Awards' top honor went to the film that attacked its issues most bluntly.
The Los Angeles social drama "Crash," which interwove plots and characters from different racial and economic backgrounds in Los Angeles, won best picture honors despite favorite "Brokeback Mountain" winning virtually every other major award it had been up for leading up the the 78th Oscars.
The ensemble film, with a cast that included Don Cheadle, Matt Dillon, Sandra Bullock and hip-hop star Ludacris, also won awards for best original screenplay and best editing.
"We are humbled by the other nominees in this category," producer Cathy Schulman said in accepting the Oscar. "You have made this year one of the most breathtaking and stunning maverick years in American cinema."
Haggis was still stunned when he came backstage to talk about the award.
"I didn't believe any of that nonsense," he said of reports that "Crash" was making a late run towards best picture. "We're still trying to figure out if we actually got this."
"Brokeback Mountain" director Ang Lee won best director for his film about the homosexual relationship that grows between two sheepherders in remote Wyoming.
"Brokeback" writers Diana Ossana and Larry McMurtry won the Oscar for best adapted screenplay, and Gustavo Santaolalla took the award for best original score.
The film had been the odds-on favorite for top honors. But "Crash" had strong support for its willingness to address prejudice with its tangled tale of crime and bigotry in the Academy's hometown.
Lee couldn't hide his disappointment backstage.
"I don't know the answer," he said when asked why "Brokeback" didn't end up as best picture. "I was backstage, enjoying the kind of buildup I was familiar with. It was a surprise this year for me."
Philip Seymour Hoffman and Reese Witherspoon were awarded best actor and actress honors.
Hoffman won for his portrayal of Truman Capote in "Capote," while Witherspoon won her Oscar for playing June Carter Cash in the Johnny Cash biography, "Walk the Line."
Backstage, Hoffman -- a versatile actor who has already been pigeonholed with the dread appelation "character actor," usually associated with supporting roles -- said he would continue to choose roles that challenged him.
"I hope all the roles I take are character roles -- lead, supporting, gaffer -- that's how I look at it. I don't look at character roles as supporting roles."
As for why he didn't bark like a dog, which was the subject of a bet about winning Oscar he made years ago, he said it never crossed his mind until he was practically off stage.
"I lost all control over my bowels up there. I thought maybe I'd bark up there for my friends ... but I was swimming in my head," he said. The pressure leading to the award announcement is "not the most comfortable environment."
Joaquin Phoenix, who played Cash in "Walk the Line" was also nominated for best actor.
Rachel Weisz won her first Academy Award for her performance as an impassioned activist who dies under mysterious circumstances in "The Constant Gardener."
And George Clooney won best supporting actor for his performance as a CIA man who starts unraveling the truth in the political thriller "Syriana."
"Wallace & Gromit in the Curse of the Were-Rabbit" was awarded the Oscar for best animated feature film and "King Kong" won for visual effects.
Director Robert Altman won an honorary Oscar for lifetime achievement.
Altman said he was receiving his award under a "false pretense" because of a "total heart transplant" about 11 years earlier.
"I got the heart of, I think, a young woman who was about in her late 30s. And so by that kind of calculation, you may be giving me this award too early. Because I think I've got about 40 years left on it, and I intend to use it," he said.
Asked backstage why he decided to disclose the operation after keeping it secret so long, Altman said, "I don't know. It just occurred to me.
"I didn't make a big secret out of it. I thought maybe nobody would hire me. There's such a stigma about heart transplants, and there's a lot of us out there."
Clooney, who also was nominated for best director and best original screenplay for "Good Night, and Good Luck," acknowledged critics who accuse the film industry of being out of touch with the American mainstream -- but he said, "It's probably a good thing."
"We're the ones who were talking about AIDS when it was just being whispered, and we talked about civil rights when it wasn't really popular ... I'm proud to be a part of this academy, proud to be a part of this community and proud to be out of touch," he said.
"Syriana," which explores the intermingling of oil and politics in the Middle East, was one of several films with social and political overtones among this year's nominees.
Weisz addressed the issue backstage after accepting her award.
"It's definitely nice being part of a moment where fiction is holding a mirror up to contemporary culture and asking questions about what's going on," she said.
"The Constant Gardener" spins a tale of pharmaceutical company chicanery across Africa.
First-time Oscar nominee Matt Dillon said the five movies up for best picture this year reflect audiences' desire for "authenticity."
"I think audiences are into authenticity at this point," said Dillon, nominated for best supporting actor for his role in "Crash" on his way down the Red Carpet into the Kodak Theatre for tonight's ceremony.
"They are interested in films that are very specific, in things that are trying to look at things that are not usually addressed in films," he told CNN.
This year's ceremony threatened to be one of the most politically charged in recent memory because of both the themes of the nominated pictures and host Jon Stewart, who made his name mocking politics on Comedy Central's late-night "The Daily Show," pointing out the absurdities of both parties through election campaigns, scandal and simple Washington inefficiency.
But Stewart confined most of his monologue's jabs to the film industry, however: He praised "Capote" for showing Americans that "not all gay people are virile cowboys." And "Capote" and "Good Night, and Good Luck," he said, "are about determined journalists defying obstacles in a relentless pursuit of the truth."
"Needless to say, both are period pieces," he added.
And after a montage of films that highlighted the social issues of their day, from "The Grapes of Wrath" to "Guess Who's Coming to Dinner," Stewart quipped: "And none of those issues was ever a problem again."
Most of the best picture nominees had something else in common: They were "small" movies, released by indies or the major studios' independent arms. In fact, critics of this year's Oscars have pointed out that none of the best picture nominees has come close to $100 million at the box office (a standard benchmark for a film's success) nor have they necessarily played well in the heartland.
But director Paul Haggis, whose "Crash" was a steady earner at the box office and then earned continued exposure through its DVD release and an appearance on "The Oprah Winfrey Show," was proud of the film's achievement -- and didn't mind that not everybody liked it.
"These are films that are telling very human stories, but risky human stories. We are so proud to be listed among them," he said. "My favorite kind of films are films in which you walk outside and you argue about them -- that you break up with your date because you disagree."
And what's next? Well, perhaps something more commercial.