Here is a long, well-argued case against a John McCain presidency by a former, high-ranking military man. It concludes with this endorsement of Barack Obama (and defacto indictment of both George Bush and John McCain):
No president can be conversant with all the problems and issues he or she will face. More important than a specific set of experiences are high intelligence, good judgment, a steady and even temperament, and a willingness to consider options presented by advisors who have been selected for their expertise.
A few months ago, I met in a small group with Senator Obama in his office to discuss a contentious security issue. People with different, even opposite, views had been invited to attend. Senator Obama listened carefully and asked penetrating questions, confirming my observations concerning his intelligence and temperament.