The purpose of the different accounting systems would seem to be to confuse everyone. Sort of like two classes of stock, and one director from the Bush, FERC & Enron era, and others who one might guess wouldn't be comfortable with that era. Hardly boring.
The non-Gaap 2010 estimate is earnings before items. The Gaap eps estimate is the actual earnings number that foes to the bottom line. If the Gaap earnings for the year are $75M than that's how much the company actually increases in value which is how return on equity is calulated.