Look back: 25 great 'Oprah' moments

Oprah's discussion of mad cow disease with animal welfare activist Howard Lyman led to Winfrey giving up hamburgers, but it also led to a whopping food libel lawsuit from the National Cattlemen's Beef Assn. in 1998. The trial was held in Amarillo, Texas, forcing Winfrey to record several shows from the Lone Star state so she could be present. The jury ruled in Winfrey's favor, but legal maneuverings and litigation lingered until 2002, when a judge decisively found Winfrey and her production company free of any wrongdoing.

Photo: Winfrey exits the courthouse after the verdict in February 1998.