I saw Bill Maher live last night. He was recording an HBO special and DVD in Portland. Maher is a good observer and funny commentator of American politics, religion, and culture. He is irreverent and holds nothing back. He's more of a traditional humorist like Mark Twain or Woody Guthrie than Jon Stewart. But he goes beyond Stewart and Lewis Black topically and stylistically. (I missed seeing Black on stage when he was in Portland a few months ago.)
These three along with Harry Shearer are four people worth listening to for insight into the state of the union with varying degrees of subtlety and style.