After all the festivities, laughter, and gift giving for the holidays, giggles and grins quickly meld into groans and glowers as Income tax Preparation Season rears its ugly face. From January 15th until April 15th, Americans fuss and fume about our ever increasing income taxes. Nevertheless, in an odd sort of way, some must enjoy the gloom since they will file for an extension, prolonging the agony of the inevitable. Marginal tax rate is the rate of tax you pay on your last (or highest) volu...