My favorite voice actors were from the 40's, 50's and 60's.
Most are in this article but in my opinion June Foray, Hans Conried, Bea Benaredet, Daws Butler and Paul Frees should have been much higher on the list. But they were the voices of my favorite cartoons and that's my bias.
Mel Blanc is listed as #1 and it's hard to argue that. He'd either be at the top or very near the top of any such list.