In terms of quality, the wonderful Tom Lehrer is the equal of anyone. He had a real job though (as a university mathematics teacher) which kept down the productivity a bit. Sadly, he only made three albums. From your side of the pond I think that Shel Silverstein, whose name also crops up here from time to time, was another jewel in your crown - (if I may say that about a proud republic!)He produced both quality and quantity.