Vanessa Carlton - "A Thousand Miles"

Vanessa Carlton's breakthrough hit "A Thousand Miles" announced her to the world back in 2002.  The song immediately shot to #1, yet her name is now on the dubious list of One-Hit-Wonders somewhere between Len and Anna Nalick.

Anna Nalick - "Breathe (2 A.M.)

Anna Nalick sounds more like a mysterious condition that affects people who consume too many pain pills, but--no, that's not the case.  The year 2005 first introduced us to Anna and her song "Breathe (2 A.M.)"; thanks to Grey's Anatomy, the song immediately gained airplay on Adult Contemporary radio stations and became Anna's one and only hit.