4. Joseph Fiennes
Taking the cake in the "unlucky younger brother" stakes is Joseph Fiennes, who has never been able to escape from under the shadow of his Harry Potter-starring brother Ralph, and has pretty much been relegated to starring in TV shows (albeit a few crackers like Flashforward and American Horror Story). However, his career began promisingly, playing William Shakespeare in the Best Picture Oscar winner Shakespeare in Love. It's a role that naturally should have shot him to the top of the Hollywood A-list, yet all that followed was a supporting turn in Enemy at the Gates, and then a steady decline in notoriety. He was once a BAFTA nominee, and now he's starring in the likes of the shoddy Camelot, which is essentially where movie stars go to die (with the exception of Eva Green, perhaps).