By Alexander Haimann, Collections Specialist & Adam M. Rosenfeld, Web Team Intern, Smithsonian National Postal MuseumConan O'Brien and Jay LenoTonight, January 22, 2010, will be Conan O’Brien’s final performance as host of NBC’s The Tonight Show, marking the end of a controversial ordeal between the late night host, Jay Leno, and NBC.The Tonight Show is one of the longest running and most famous television programs of all time. It's first three long-running hosts, Steve Allen, Jack Paar and Johnny Carson elevated the show to the top of American television between 1954 and 1992.