"The Hurt Locker" has proved the little guy can win it all, taking home six Oscars, including best picture and best director for Kathryn Bigelow, while Sandra Bullock and Jeff Bridges scored the top acting nods Sunday night.

The war drama, which has become the lowest-grossing best picture winner of all time, beat out blockbuster "Avatar," as well as eight other nominees, including "Up in the Air," "Precious" and "Inglourious Basterds."

Bigelow's win makes her the first woman to ever win a best directing Oscar.

"It's the moment of a lifetime," said Bigelow, choking back tears, as she accepted the directing award moments before Tom Hanks announced the best picture win.

She thanked writer Mark Boal, who picked up an Oscar earlier in the night for original screenplay, for bringing the story to life.

"I would just like to dedicate this to the woman and men in the military who risk their lives on a daily basis … May they come home safe."

Her win puts an end to the much-talked-about rivalry between Bigelow and ex-husband James Cameron, whose big-budget flick "Avatar" took home three awards earlier in the evening for art direction, cinematography and visual effects.

Leading up to the awards show, 'The Hurt Locker' and 'Avatar' had been tied at nine nominations each.

Sandra Bullock won the best actress Oscar, beating out veteran Meryl Streep, for her role as a tough talking well-to-do woman who takes in a homeless teen in "The Blind Side."

A seemingly stunned Bullock took the stage and asked: "Did I really earn this or did I just wear you all down?"

The actress addressed her other competitors, including Streep who holds the record for the most Oscar nominations at 16, noting that she was "such a good kisser." The two shared a smooch when they shared a win at the Critics' Choice Movie Awards.

She teared up when thanking her mother for allowing her to follow her heart.

The actress, who was largely favoured to win after picking up a number of notable awards leading up to the Oscars, also took home another award this weekend -- a worst actress Razzie for her performance in "All About Steve" opposite Bradley Cooper. It makes her the first person to ever win both awards in the same weekend.

Minutes earlier, Jeff Bridges took the best actor award for his role as a down-and-out country singer in "Crazy Heart."

An animated Bridges let out more than a few excited yelps, and thanked his parents for turning him onto such a profession.

"This is honouring them as much as it is me," said Bridges, who also thanked his co-stars and wife of 33 years.

The movie also won an Oscar earlier in the night for best original song for "The Weary Kind (Theme from Crazy Heart)" by Ryan Bingham and T Bone Burnett.

"The Cove" took home the Oscar for best documentary, while Mo'Nique was honoured for best supporting actress.

After sweeping the awards show circuit thus far, Mo'Nique took home her first Academy Award for her role as an abusive mother in "Precious." Mo'Nique fought back tears as she thanked the Academy for showing it can be about the performance and not the politics.

She also thanked the likes of Oprah Winfrey, who co-produced the film and strongly threw her support behind it, as well as her husband Sidney.

"Thank you for showing me that sometimes you have to forgo what's popular in order to do what's right and baby, you were so right," said Mo'Nique, as she clutched her golden statue.

Christoph Waltz took home Best Supporting Actor early in the night for his role in "Inglourious Basterds." Waltz accepted his first Oscar with much grace as he talked about how everyone from Brad Pitt to director Quentin Tarantino played a role in his success.

"This is your welcoming embrace and there's no way I can ever thank you but I can start right now," said Waltz.

To no one's surprise, "Up" nabbed the Oscar for best animated feature film and later picked up a second award for Best Original Score.

The Best Adapted Screenplay Oscar went to Geoffrey Fletcher for "Precious: Based on the Novel ‘Push' by Sapphire," an award that many thought would go to Canadian writer/director Jason Reitman for "Up in the Air."

The awards show kicked off with something new -- introductions of all the best actress and actor nominees, who stood beaming on the stage as their names were called, followed by a singing and dancing number by Neil Patrick Harris in a flashy tuxedo jacket. The surprise guest ran through a musical routine, complete with dancing Vegas-type showgirls, while he made punchy references to the nominated films.

Hosts Steve Martin and Alec Baldwin dropped in shortly after, on a feather-covered ring apparatus from above.

Making references to many of the nominated films, Martin and Baldwin exchanged barbs as they complimented the performances of everyone from Christopher Plummer, Helen Mirren and Meryl Streep to the cast of "Precious."

The duo then put their 3D glasses on as they addressed James Cameron and poked fun at the rivalry between the "Avatar" director and his ex-wife Kathryn Bigelow, and commented how she had sent him a gift basket with a timer and how he sent her a Toyota in return.

A tribute to famed director John Hughes, who passed away in 2009 from a heart attack, included a montage of some of his most famous films "The Breakfast Club," "Sixteen Candles" and "Home Alone," as well as touching personal addresses from some of the cast, including Ally Sheedy, Macaulay Culkin and Matthew Broderick who wished him "Danke Schoen," quoting a famous line from "Ferris Bueller's Day Off."

Tributes were also played to the likes of Patrick Swayze, Jean Simmons, Brittany Murphy and Michael Jackson, with a montage set to a live performance of "In my Life" by James Taylor.

In a comic relief moment, Ben Stiller took the stage dressed as an Avatar to present the award for best makeup. He spouted out some Navi-like words, which he then translated.

"That means this seemed like a better idea in rehearsals," said Stiller, who went on to say he either chose that or a Nazi uniform, but the show already seemed to be a little "Hitler heavy."

The award went to "Star Trek," which was largely ignored by the Academy, after many thought the best picture category had been expanded to include that very film.

"El Secreto de Sus Ojos" took home the Oscar for best foreign language film.