Leelee Sobieski
Leelee Sobieski played the title character in a Joan of Arc biopic and landed several small dramatic roles throughout the 1990s. She was up for a role in Interview with the Vampire, but Kristen Dunst ended up winning it instead. Sobieski's once prolific career flattened out pretty quickly after the early 2000s.
Sam Worthington
James Cameron gave Sam Worthington his arguably best role in Avatar. He even auditioned to play James Bond in Casino Royale, but the part was given to Daniel Craig. Other than the Cameron-created sci-fi film, Worthington hasn't done much since then.