Romney is screwed with the media no matter who he picks. Picks a female or a person of color; token, pandering for women and minority votes. White guy; he's a racist. Throw in conservative of any gender or color; See, he really wants to kill old people, dogs, children and nuke California.
Romney needs to pick whoever he thinks could step into the Presidency. Then he needs to spend a couple of days defanging Obama and the media mud, sleeze and lies by publicly, in a very strong way, with paid ads of his own, not super pac money, to tell Americans that he isn't going to respond to any of Obama and media lies, sleeze and mud. That the race is too important to respond to this juvenile, childish dreck. Then he needs to strongly make a point by point case with respect to what he plans his presidency's platform is all about and why and hammer that every day till election day.