I haven't seen many, but the ones I have seen I'd say Jon Stewart easily takes the cake. Colbert was nice in his Report but he absolutely sucks ass in the Late Show. The format just doesn't suit him.
Since Jon and Stephen are basically dead now I have to turn to John Oliver, though I don't know if I can call his show legally Late Night.
If you demand respect or gratitude for your volunteer work, you're doing volunteering wrong.