You didn't say song. "Romeo and Juliet" obviously. "Pride and Prejudice". "Wuthering Heights" (my top three).

Others worth noting: "Lady With a Pet Dog" (Chekov); "War and Peace" (Natasha and Andrei).

In terms of sheer insane obsessive love, "Lady of Shalott" (Loreena McKinnet's version comes to mind) is pretty close to the top.   

yours,

Peter T.