Cook picked "The World I Know" by Collective Soul. It's groovy and easily his best performance of the night. He tears up at the end.
"One of the cool things about you is that you're showing people tonight a lot of different sides of David Cook," Jackson said. "This is the kind of record you could make and get by with."
"It was a beautiful song, but I'm going to be honest with you it was completely and utterly the wrong choice for you on the night," Cowell said.
Cowell thought Cook should have gone with this:
Archuleta went with reprising "Imagine." The song sounds even better with a string orchestra.
"Dude, you are so good tonight," Jackson said. "You are exactly what this show is about: finding the best singer we can find and the best singer is right there."
"You were stunning tonight," Abdul said.
"We've taken a little bit of stick this year in the competition, but at the end of the day this show is about finding a star," Cowell said. "Tonight, we've witnessed one of the great finals, but here's the difference. In my opinion, David, you came out here to win and what we witnessed was a knock out."