Letterman was extremely boring, Colbert even more. I stopped watching before Jeb.
Colbert had some funny bits now and then (like, “I don’t see race. I didn’t know I was white until somebody told me.”)
I couldn’t stand Letterman.
I liked Conan O’Brien’s routine where he’d interview a big picture of a celebrity (like Arnold Schwarzenegger) where only the lips moved, a la Clutch Cargo.