The Finches were long known for good breeding and fairness. What are they known for now?

I believe the answer to this question is that they were known as the family (Atticus' family) of the man who was defending Tom Robinson, a black man.

“There’s his chillun,” or, “Yonder’s some Finches.” Turning to face our accusers, we would see only a couple of farmers studying the enema bags in the Mayco Drugstore window. Or two dumpy countrywomen in straw hats sitting in a Hoover cart.