Condi Rice.
I ditto that!
Not gonna happen. Here's why: There is only one person in the history of the United States of America who won the Presidency in his first electoral victory who hadn't been first credited with victory in a war. That person was Herbert Hoover.
Hillary is smart enough to know that she can't just jump from First Lady to Presidential hopeful. She knew that she'd have to do time as an elected official -- as did Robert F. Kennedy and, to a lesser extent, John Edwards -- before she could possibly be taken seriously.
Right now, I can't think of who would be a formidable challenger to Hilliary, but it will have to be someone who has won an election before. For more on this, check out my 2000 thread, "PRESIDENT OF THE UNITED STATES IS NOT AN ENTRY-LEVEL POSITION."