4. Steve Allen
Before David Letterman, Johnny Carson and even Jack Paar, there was Steve Allen. Allen practically invented the late night talk show when he became the first host of The Tonight Show in 1954. It was the birth of the opening monologue, the desk and even the celebrity interview. Over 60 years later, this model has somehow persisted. Allen left after just three years, but it was an extremely formative time for the medium and his influence cannot be overstated. Unfortunately, in his later years he aligned himself with the Parents Television Council and pushed to get people like Howard Stern thrown off the airwaves. He was also a very vocal critic of rock & roll, despite featuring many of the early stars on his show.