3. Conan O'Brien
For all that NBC did to destroy Conan O'Brien, you have to give them credit for agreeing to put him on the air in the first place. After all, he was once a completely unknown Simpsons and Saturday Night Live writer that Lorne Michaels tapped to take over for Letterman at 12:30. Ratings were very weak and the critics were harsh, but NBC stuck by their guy and let him find his footing. By 1996, he was just about the funniest thing on television. He was the natural choice to replace Jay Leno as the host of The Tonight Show, but we all know how that went. It's hard to replace somebody when that person doesn't actually leave. Thankfully, Conan landed safely on TBS and seems in no danger of getting the axe in the foreseeable future.