"You wait for a voice like that for a lifetime," said music mogul Clive Davis, who shepherded Houston's career for decades.
The service had lighthearted moments too Kevin Costner imagining a young Houston using her winning smile to get out of trouble, Houston's cousin Dionne Warwick offering short insights about the singer.
Others were more mournful; singer Ray J., who spent time with Houston during her last days, broke down crying. His sister, singer Brandy, put her arm around him. Cissy Houston and Houston's daughter, 18-year-old Bobbi Kristina, clutched each other. Toward the end of the service, Bobbi Kristina and Ray J. embraced at length and spoke. Others gathered near the front of the church and hugged each other.
The most powerful moment was reserved for the end. As Houston's casket was carried out, her hit "I Will Always Love You" played. Bobbi Kristina began crying, and the sobs of Houston's mother rang throughout the church.
"My baby!" she wailed.
Stevie Wonder and Oprah Winfrey were among the biggest names gathered to mourn Houston, along with Hudson, Monica, Brandy and Jordin Sparks representing a generation of big-voiced young singers who grew up emulating her.
Costner, her co-star in "The Bodyguard," which spawned her greatest hit, remembered a movie star who was uncertain of her own fame, who "still wondered, 'Am I good enough? Am I pretty enough? Will they like me?'"
"It was the burden that made her great and the part that caused her to stumble in the end," Costner said.
Filmmaker Tyler Perry praised Houston's "grace that kept on carrying her all the way through, the same grace led her all the way to the top of the charts. She sang for presidents."
Warwick presided over the funeral, introducing speakers and singers.
Houston's mother was helped by two people on either side of her as she walked in and sat with her granddaughter and other family to begin the service. Houston's ex-husband, Bobby Brown, briefly appeared at her funeral, walking to the casket, touching it and walking out. He later said in a statement that he and his children were asked repeatedly to move and he left rather than risk creating a scene.
As the funeral began, mourners fell quiet as three police officers escorted Houston's casket, draped with white roses and purple lilies. White-robed choir members began to fill the pews on the podium. As the band played softly, the choir sang in a hushed voice, "Whitney, Whitney, Whitney."
Close family friend Aretha Franklin, whom Houston lovingly called "Aunt Ree," had been expected to sing at the service, but she was too ill to attend. Franklin said in an email to The Associated Press that she had been up most of the night with leg spasms and sent best wishes to the family. "May God bless and keep them all," she wrote.
A program featuring a picture of Houston looking skyward read "Celebrating the life of Whitney Elizabeth Houston, a child of God." Pictures of Houston as a baby, with her mother and daughter filled the program.
"I never told you that when you were born, the Holy Spirit told me that you would not be with me long," Cissy Houston wrote her daughter in a letter published in the program. "And I thank God for the beautiful flower he allowed me to raise and cherish for 48 years."
"Rest, my baby girl in peace," the letter ends, signed "mommie."
The service marks one week after Houston, one of music's all-time biggest stars, was found dead in a Beverly Hills hotel in California. A cause of death has yet to be determined.
To the world, Houston was the pop queen with the perfect voice, the dazzling diva with regal beauty, a troubled superstar suffering from addiction and, finally, another victim of the dark side of fame.
To her family and friends, she was just "Nippy." A nickname given to Houston when she was a child, it stuck with her through adulthood and, later, would become the name of one of her companies. To them, she was a sister, a friend, a daughter, and a mother.
"She always had the edge," the Rev. Jesse Jackson said outside church Saturday. "You can tell when some kids have what we call a special anointing. Aretha had that when she was 14. ... Whitney cultivated that and took it to a very high level."
A few fans gathered Saturday morning hours before the service as close as they could get to the church, some from as far away as Washington, D.C., and Miami. Bobby Brooks said he came from Washington "just to be among the rest of the fans."
"Just to celebrate her life, not just her death," said Brooks, "just to sing and dance with the people that love her."
Others were more entrepreneurial, setting up card tables to sell silk-screened T-shirts with Houston's image and her CDs. But only the invited would get close to the church; streets were closed to the public for blocks in every direction. But their presence was felt around the church, with a huge shrine of heart-shaped balloons and personal messages that covered the street corner around the church entrance.
Houston's death marked the final chapter for the superstar whose fall from grace while shocking was years in the making. Houston had her first No. 1 hit by the time she was 22, followed by a flurry of No. 1 songs and multi-platinum records.
Over her career, she sold more than 50 million records in the United States alone. Her voice, an ideal blend of power, grace and beauty, made classics out of songs like "Saving All My Love For You," ''I Will Always Love You," ''The Greatest Love of All" and "I'm Every Woman." Her six Grammys were only a fraction of her many awards.
But amid the fame, a turbulent marriage to Brown and her addiction to drugs tarnished her image. She became a woman falling apart in front of the world.
Her last album, "I Look To You," debuted on the top of the charts when it was released in 2009 with strong sales, but didn't have the staying power of her previous records. A tour the next year was doomed by cancellations because of illness and sub-par performances.
Still, a comeback was ahead: She was to star in the remake of the movie "Sparkle" and was working on new music. Her family, friends and hard-core fans were hopeful.
The funeral is for invited guests only. Houston is to be buried next to her father, John Houston, in nearby Westfield, N.J.
Contributing to this report were AP Global Entertainment and Lifestyles Editor Alicia Quarles and Entertainment Writer Mesfin Fekadu.
Nekesa Mumbi Moody is the AP's music editor. Follow her at http://www.twitter.com/nekesamumbi