Sandra Bullock PEOPLE Cover

It's no surprise that PEOPLE magazine's shocking Sandra Bullock baby cover was a huge seller, but it hasn't yet replaced the magazine's biggest-selling baby exclusive ever -- the August 2008 issue featuring exclusive photos of Brad Pitt and Angelina Jolie's newborn twins, Knox Leon and Vivienne. However, Sandra's big bombshell may have been the most profitable cover in the magazine's history. Find out why after the jump!