Right after graduating from high school in 1978, I buggered off for a three-week trip to England; while I was there, 9 of the 10 top-ten songs on BBC 1 radio were from "Grease" (title song, "Hopelessly Devoted to You", "Sandy", "You're The One That I Want", so on and so on). It was like a religion over there.
The guiltiest pleasures on my Creative Zen are probably this and this.