I think most people remember the Righteous Brothers' big radio hit version of "The Unchained Melody". Here's an earlier recording by Sam Cooke. I think it's great...
Just came across this one yesterday. Foo Fighters AKA "Dee Gees" (disco Foo Fighters)
On the original by the Bee Gees, John Travolta's dancing scene begins 20 seconds in. Don't think I've seen that sequence since the movie came out way back when.