Clearly, Norm McDonald is the favorite here...there must be a reason he hasn't been on yet. That's one you could go a deep dive with. Also would like to hear Tom Papa, Anjelah Johnson, or (and I'm going to get some big time boos here) Dane Cook - who was unfairly thrown into the same dumpster as Nickelback IMO.
Although non-comedians can be good - Charles Barkley is a great example - Robert Caro was not good, and probably my least favorite. I'll listen to Terry Gross for that kind of thing.