David Cook was crowned "American Idol" Wednesday, his smooth showmanship defeating a favored young challenger who swept the judges' praise the previous night.

"This is amazing. Thank you," Cook said, after bending to the stage floor with emotion when the results were announced.

Defeated was David Archuleta, 17, a fresh-faced balladeer groomed most of his life for the stage by his jazz musician father. Archuleta was widely praised by the judges for a slam-dank performances in the final round.

Cook, 25, who grew up outside Kansas City, Mo., and most recently worked as a bartender while playing in clubs in Tulsa, Okla., was a rocker in the style of one of the show's most successful runners-up, Chris Daughtry.

He wasn't even going to audition — he accompanied his brother to the tryouts to support him and a producer talked him into giving it a try.

He wound up in the finals.

Wednesday's "Idol" finale, timed to fall on the last night of May ratings sweeps, featured all 12 finalists of TV's No. 1 show.

Among the parade of stars entertaining: Donna Summer, comedian Jimmy Kimmel ("Hey, I valet parked outside; how much do I tip Sanjaya?"), ZZ Top, OneRepublic, Gladys Knight, Ben Stiller, Carrie Underwood and George Michael.

Wednesday's show opened with host Ryan Seacrest announcing that the contest wasn't close — a 56-44 percent split among the 98 million votes cast, exceeding last year's total by more than 20 million.

But it was widely judged a lackluster year for the popular talent show.

While it still delivered a blockbuster audience, ratings were down about 8 percent and it lacked strong personalities and breakout talent of previous seasons.

Judge Randy Jackson wouldn't agree. "This has been one of the strongest years ever," he said before the winner was announced.

Simon Cowell, who had been unsparing with criticism of both at times, congratulated the two finalists, praising them for taking chances.

"For the first time ever, I don't care who wins," Cowell said. "I think you've both been terrific."