(Reuters) - Soul singer Adele triumphed in her return to music's stage on Sunday, scooping up six Grammys and winning every category in which she was nominated including album of the year for "21" and best record with "Rolling In the Deep."As joyous as the show was for Adele, it was equally as serious with tributes to late pop star Whitney Houston, who died suddenly on Saturday. She was remembered by fellow artists in acceptance speeches and songs. Jennifer Hudson sang Houston's signature hit "I Will Always Love You," and Grammy host LL Cool J offered a prayer for Houston's family, friends and fans.

But it was Adele who stole the show. The 23-year-old, who has taken the music world by storm, underwent surgery on her vocal cords late last year and had been resting her voice on doctor's orders until music's biggest night. The British singer took the stage to belt out "Rolling In the Deep," and finished to a standing ovation.

Adele claimed three of the music industry's top awards, album, record and song of the year, and added best pop solo performance, pop vocal and short video to her stack of trophies.

"Thank you so much. This is ridiculous," she said upon accepting the record of the year Grammy. "I want to say thank you to every radio programmer and broadcaster that has been playing 'Rolling in the Deep' ... because I know it's not really a pop record." She flashed a big smile and a thumbs up.

Rockers Foo Fighters were the other big winners, picking up five Grammys including best rock performance for the hit "Walk."

"This is a great honor because this record was a special record for our band. Rather than go to the best studio ... we made this one in my garage with some microphones and a tape machine," said frontman Dave Grohl. "It shows that the human element of making music is what's most important."

But as jubilant as the audience was for Adele and as much as Foo Fighters rocked the house, Grammy organizers were equally as serious about the death of Houston, whose body was found in the bathtub of her Beverly Hills hotel room. The cause is still unknown.

Host LL Cool J took the stage and offered a prayer for Houston, her fans and her family. "Although she is gone too soon, we remain truly blessed by her musical spirit," he said.

Other highlights included a Beach Boys reunion and a lifetime award for Glen Campbell, who sang "Rhinestone Cowboy."

Rousing performances came from Taylor Swift singing her hit "Mean," Bruce Springsteen and the E Street Band, Chris Brown, Coldplay and Rihanna. Alicia Keys and Bonnie Raitt sang "A Sunday Kind of Love" from Etta James, who also died in 2012.

(Reporting By Bob Tourtellotte; Editing by Eric Beech)