Yeah, Hank and Dan Castelineta (I know I spelled that wrong :) are my favorites.
The entire cast of the Simpsons was on Inside The Actors Studio once and I surprised to know that that was the first time all of them had been together in one place in months.
They mostly record their lines separately, sometimes weeks apart, and hardly see each other. I was so disillusioned :-/
A few years ago some radio station around here had Dan Casawhatever on. He started doing the Homer voice. It was very, very disorienting to hear Homer's actual voice coming out of my car radio and interacting with the hosts. It was cool, but weird.