Personally I follow the presidential race from the vantage point of generalisation and am more interested in the prospect of seeing what a new breed of president would be like.
Would a woman or a black man perhaps usher in a new perspective in the nations consiousness as a whole? The States needs a big sea-change in perception to improve its persona in the world at large.
But... If pushed? I would argue that Obama is the way to go.
Hilary Clinton as a woman may bring a totally new perspective to the post but she is still Clinton's wife and that, carries with it many different kinds of baggage. You need only look at George W's vendetta to finish his father's work in Iraq to see that a prior relationship to the post isn't conducive to a radical, clean break. No matter the intentions there will always be echos of his career being used for or against hers, by allies, opponents and the media.
Back in the 90's a heard a radio interview where the actor Will Smith, lamented that he didn't think he'd see a black president in his life time (I think he may have been asked if he would ever run for office). Lets hope he's wrong (and decides to run some day!!!).