Forest Whitaker won best actor laurels on Sunday for his role as brutal Ugandan dictator Idi Amin in The Last King of Scotland.
The Oscar win -- the first for 45-year-old Whitaker -- marked the actor's triumphant return to the silver screen after an extended run of behind-the-camera work.
Whitaker, struggling for words before pulling out a written text, described his Oscar victory as a triumph over his humble beginnings in east Texas and the streets of south-central Los Angeles.
"When I was a kid, the only way I saw movies was from the backseat of my family's car at the drive-in. And it wasn't my reality to think I would be acting in movies. So, receiving this honor tonight tells me that it's possible," he said.
"Through our combined belief we can create a new reality," he added, thanking the people of Uganda for their spirit. Whitaker beat out Leonardo DiCaprio (Blood Diamond), Ryan Gosling (Half Nelson), Peter O'Toole (Venus) and Will Smith (The Pursuit of Happyness) to take home the coveted statuette.
The Departed wins best film Oscar
Crime thriller The Departed, director Martin Scorsese's tale of corruption among the Boston police, won the Oscar for best film.
The Departed competed for the world's top film award with four other movies including cultural drama Babel, comedy Little Miss Sunshine, World War II saga Letters From Iwo Jima and The Queen, about the British royal family.
British actress Helen Mirren won the best actress Oscar on Sunday for her performance as Britain's Queen Elizabeth II in the movie The Queen, a victory that had been widely expected.
It was the first Oscar for Mirren, 61, who had already won more than 20 other major awards for her sympathetic portrayal of an out-of-touch monarch in the days after the sudden death in 1997 of Princess Diana.
In a surprise victory, veteran actor Alan Arkin, who plays an irascible grandfather in Little Miss Sunshine, won the best supporting actor.
"More than anything, I am deeply moved by the open-hearted appreciation our little movie has received," Arkin said, after joking that he almost didn't get the job because the directors thought him too virile.
It was a surprise victory over Eddie Murphy, who won several other major Hollywood awards this year for his role as a soul singer with a drug habit in musical Dreamgirls.
But road comedy Little Miss Sunshine has been a hit with fans, and Arkin's role was a favorite because while the grandfather snorts heroin and says some mean things to his family, he also dispenses many pearls of wisdom.
The low-budget Sunshine has won wide acclaim for its story about a family of losers who learn what it means to be winners through the attitude of a 10-year-old girl who wants to be a beauty queen.
First time host Ellen DeGeneres cranked out the comedy and took swipes at the likes of Dame Judi Dench, Peter O'Toole and Leonardo DiCaprio. In one bit, she appeared backstage chatting with a crew member and talking about how Dench, who is nominated for best actress in Notes On a Scandal, failed to come to the Oscars due to knee surgery.
"She's having knee surgery," she said, then paused for impact, "on her eyes." Only minutes later, she reappeared onstage and said she had made a mistake. "It was her boobs," DeGeneres joked.
8 nominations; no win?
The host, who appeared in a burgundy tuxedo, teased 74-year-old Peter O'Toole about his eighth nomination for his role in romantic drama Venus by wondering why he has never won.
"Eighth nomination, is that right?" DeGeneres asked. "You know what they say, 'Third time's a charm.'"
The show began with several minor awards. Mexican film fantasy Pan's Labyrinth won two Oscars for best art direction and make-up. Movie musical Dreamgirls took home the Academy Award for sound mixing, and Letters From Iwo Jima won the award for sound editing.
The Oscars are given out annually by the Academy of Motion Picture Arts and Sciences and are the world's top film honors. Experts believe there are many wide open races in the major categories, especially best film, and Arkin's victory only highlighted the notion that many surprises were expected.
Little Miss Sunshine and cultural drama Babel were two leading picks for best film, but crime thriller The Departed, British royals saga The Queen and World War II tale Letters From Iwo Jima were not far behind.
Helen Mirren was clear frontrunner for best actress, and Martin Scorsese was expected to win the best director for The Departed. But they were considered the only two shoo-ins.
"If it isn't his (Scorsese's) year, I will have to eat someone's hat," actress Jodie Foster told reporters on the famed red carpet leading up to the Oscars.
The best actor category was expected to boil down to a race between Forest Whitaker as the brutal dictator Idi Amin in The Last King of Scotland and veteran Peter O'Toole as an elderly man in love with a young woman in Venus.