By 2006, it appeared the pop princess was ready to abdicate her throne, her marriage to Kevin Federline and custody of their two boys, Sean Preston and Jayden James. A months-long saga of bad behavior that included multiple flashes of her private parts, countless nights on the town and allegations of drug and alcohol abuse culminated in February 2007 with Spears buzzing off her famous locks at a Tarzana, Calif., hair salon while photographers snapped away outside. Later that year, she gave what has become a widely ridiculed performance at the VMAs.
It took nearly two years and her father taking charge of her life before Spears regained her footing. Musically, she ends the decade on an up note. Her 2008 song "Womanizer" put her back at the top of the singles charts for the first time since the 1990s. And her album "Circus" is approaching double-platinum status, while her 2009 concert tour was the year's highest-grossing in the United States .
Michael Jackson spent most of the decade embattled.
A conflict with Sony over 2001's "Invincible," Jackson's last album to feature new material while he was alive, led to Jackson's exit from the label and a cancellation of all promotion related to the album.
His 2003 interview with Martin Bashir, now a co-anchor of ABC News' "Nightline," was a PR nightmare, with Jackson seen dangling his son Blanket from a hotel window and discussing sleeping arrangements with a teenage boy. Shortly after the Bashir interview aired, Jackson was charged with seven counts of child molestation. He was acquitted after a long trial in 2005.
But his troubles continued. Nearly bankrupt, he was forced to sell his famous Neverland Ranch. He also struggled with prescription drug addiction.
In 2008, he announced his comeback tour, a series of 50 concerts in London. He never made it. He died of cardiac arrest in his Los Angeles home on June 25.
Ironically, it took death to bring Jackson back. Three of Jackson's albums were in the top three spots on the Billboard charts in the weeks after his death. The documentary, "This Is It," pieced together from rehearsal footage, became the highest-grossing concert film of all time.
Jackson left the decade and this world on top.
There's nothing like proving Simon Cowell wrong, as Jennifer Hudson, a former 2004 "Idol" hopeful, knows. Hudson was booted from the show in the seventh round after Cowell commented that she was "out of her league."
But Hudson got the final word. In 2006, she was lauded for her role as Effie in the hit movie "Dreamgirls" and later went on to win the Oscar for best supporting actress.
After seeing Hudson perform on "The Oprah Winfrey Show," Cowell admitted his mistake: "I'd like to be the first to admit a massive dose of humble pie."
But just as Hudson was starting to promote her first album, she suffered a huge blow: her mother, brother and young nephew were found murdered in Chicago. Mourning her lost loved ones, Hudson stayed out of the spotlight and leaned on her fiance, David Otunga.
When she finally returned to the limelight, she gave a flawless performance of the national anthem at the Super Bowl in February 2009 and picked up a Grammy Award later that month.
At the beginning of the decade, Whitney Houston's good girl image had all but faded.