There is no need for bigger quanity as bigger amount of clones make original just weaker. Instead I rather to see about six shadow clones which have much greater quality and do not make Original weaker too much.
This is an interesting thread with a lot of well constructed arguments, and it's definitely a subject I think about often. Obviously, the answer to this question is highly subjective, and I don't believe there is a single right answer. I like reading everyone's opinion on the matter, though, and I hope this discussion goes on.