Foo Fighters - 'Everlong' (2000)
David Letterman has been a huge fan of the Foo Fighters since they first played on the show back in 1995, and he's said many times that he's obsessed with their song "Everlong" — Paul Shaffer and the CBS Orchestra have played it roughly a thousand times coming in and out of commercials. So when the host came back from heart surgery in 2000, it made perfect sense to bring in Dave Grohl and the boys to play it. "My favorite band playing my favorite song," he said. "Ladies and gentleman, Foo Fighters!" This was one of the most emotional episodes in Letterman history, and the Foos rose to the occasion, even letting Paul play a little organ.