The top Grammy winners came from eclectic musical genres, from R&B to bluegrass to rock 'n' roll.

The singing sensation Alicia Keys and the old-time country soundtrack to O Brother, Where Art Thou? each racked up five Grammys, while the legendary rock group U2 took home four awards.

Keys was named best new artist. Her song "Fallin" was named best R&B song, best female R&B vocal performance and song of the year, and her Songs in A Minor won for best R&B album.

"I'd like to dedicate this to just thinking outside the box and not being afraid of who you are no matter what you do," the 21-year-old Keys said after winning for best rhythm 'n' blues album.

The O Brother soundtrack scored a surprise victory for album of the year, beating out the anticipated favorite, U2. The popularity of the country album stunned the music industry, and ultimately earned a producer of the year award for T Bone Burnett, the man who conceived of the album.

"We are filled with gratitude not only that you have chosen to honor this work in this way, but also because we were afforded the chance to make it in the first place," said Burnett.

U2, which had a leading eight nominations, won the coveted record of the year Grammy for "Walk On," marking the second straight year they won that top category. Last year, it was for "Beautiful Day."

"The songs do change their meaning. Music changes shape to fit the predicament it finds itself," the band's lead singer Bono said. "This year the predicament was a very different America. We've always loved coming here. But this year I've rediscovered my love of America, the great idea as opposed to the great country."

At the opening of the show, host Jon Stewart of The Daily Show poked fun at increasing security. He pretended to set off a metal detector while on stage. Two guards then stripped Stewart and left the comedian in his boxer shorts.

"Remember when security was tight because Eminem was going to sing with Elton John?" Stewart joked.

Some of the stand-out performances of the evening came from Outkast whose "Ms. Jackson" turned the stage into a visual and literal playground with children frolicking amongst the singer, and "Lady Marmalade" sung by the scantily-clad foursome: Christina Aguilera, Lil' Kim, Mya, and Pink.

One surprise of the night was that India.Arie, who had been nominated for seven awards, didn't win in any category.

Besides best album, O Brother won best compilation disc and garnered Ralph Stanley, who performed "O Death," best male country vocal. It also won the Soggy Bottom Boys the award for best country collaboration with vocals.

Stanley's win came two days after he celebrated his 75th birthday.

"I think this is the best birthday I've ever had," said Stanley.

Other winners were Eve and Gwen Stefani, for best rap/sung collaboration for "Let Me Blow Ya Mind"; Sade, who won best pop vocal album for Lovers Rock; and Linkin Park, which won best hard rock performance for "Crawling."

Canadian newcomer Nelly Furtado bested veterans like Sade and Janet Jackson with a win in the pop female vocal category.

"Cool! Highly unexpected," said a buoyant Furtado.

Overall, the evening was high-spirited in a time when the music industry is embattled and sales are down. Recording companies blame the slump mainly on free downloading from the Internet.

Recording Academy President C. Michael Greene gave a stern speech midway through the show.

"No question the most insidious virus in the midst of this illegal downloading of music is piracy on the Net," he said. "It goes by many names and its apologists offer a myriad of excuses. This illegal file sharing and ripping of music is pervasive, out of control, and it's oh, so criminal."

The evening ended on a touching, but somber note with country singer Alan Jackson crooning his post-Sept. 11 anthem "Where Were You (When the World Stopped Turning)."

The Associated Press contributed to this report.