Among the late-night talk show hosts ... I usually like to watch Jay Leno over David Letterman in the same time slot. Jimmy Fallon is incredibly clever in everything he does, but Craig Ferguson makes me laugh harder. Ferguson is even more amazing in that he ad-libs every monologue. I never stay up late enough to watch Jimmy Kimmel or any of the others in that time slot.
I never liked Conan O'Brian and I'm not at all sorry that he got fired from NBC's Tonight Show. I'm not sure if his show on cable is still on ... its a moot point, because I wouldn't watch it even if its still on.