There's been plenty of turmoil atop Fortune's annual Most Powerful Women list. Meg Whitman crashed the party, coming in at No. 9 when she became CEO of Hewlett-Packard. (As CEO of eBay, she was on the list from 1999 to 2007.) Longtime MPW Carol Bartz lost her job as CEO of Yahoo -- and her place on the list -- while Oprah Winfrey fell 10 spots to No. 16, her power and influence in flux without the platform of her eponymous syndicated talk show.
Perhaps the biggest change of all? Kraft CEO Irene Rosenfeld takes the No. 1 position from PepsiCo chief Indra Nooyi, who topped the list for five years. This ranking is all about power, and while Nooyi runs the bigger company, Rosenfeld's decision to split Kraft into two entities shows she has it and knows how to use it.