|Let me tell you sometin', Meathead.|
Is Tony Soprano the greatest TV character of all time?
Try: Archie Bunker, Lucy Ricardo, James T. Kirk, George Costanza, Zachary Smith....
(I must say that I cannot stand most sitcoms, but there you go.)
There is a tendency to pick recent, or recent-ish, television shows and their characters as "the best ever"; time must pass. A little 'history' needs to accumulate in order to make such bold proclamations -- forgetting subjectivity, of course.
Personally, I think the answer to the above question is a no-brainer: "Gladys Crabtree"