How do you feel about letting a child "ride out" a fever?

Do you think a child should be given a fever-reducer such as acetaminophen or ibuprofen at the first sign of a fever or once a fever reaches a certain temperature?

Or, do you feel a fever is the body’s way of fighting an illness and let the fever continue untreated? At what degree of fever, if any, do you begin to treat it?

For argument’s sake, let’s assume fever and a cough are the only symptoms.