Name some actors who so distinguished a role that you can't imagine anyone else playing it. Tom Hanks as Jimmy Dugan in A League Of Their Own. Sally Field as Norma Rae. Bryan Cranston as Walter White. Russell Crowe as John Nash in A Beautiful Mind. Colin Firth as King George VI in The King's Speech. I'll even throw in Julia Louis-Dreyfus as Elaine Benes. Have fun, but don't be too obscure. Colin Clive as Henry Frankenstein doesn't count.