1. McCain is proposing actual concrete changes while Obama is mired in rhetoric. McCain proposed that they both adopt voluntary campaign financing reform; Obama rejected him. McCain is talking about ending partisan fighting and working together to get things done. McCain is talking about an end to negativity in campaigns. It really goes on much beyond that... Some argue that McCain is insincere, but I think his record and his current talk are really convincingly very sincere.
2. McCain might very well ask Secretary of State Condoleeza Rice to be his running mate - both black and a woman. Rice is only 53, so we could easily have 12 more years of Republican presidents.
Rice is pretty impressive. Check out this video. She's good. Apparently her speeches are even better. As National Security Advisor at the start of the Iraq war she argued against the Rumsfeld strategy, but the then-Secretary of State overruled her. When Rumsfeld was ousted she was made Secretary of State to clean up the mess, and by some standards she has made progress in Iraq and Afghanistan - at least enough improvement to make a case that the McCain/Rice ticket is more qualified than Obama to get the US out of there.
If the election is about change and getting out of Iraq, Obama will face a formidable challenge in McCain/Rice. The main counter-attack is that McCain-Rice represents more of the same (a new nickname for McCain is "McSame"). There's some truth to that... not just in Iraq and Afghanistan, but across the board in policy. The confusing aspect is that McCain also offers real change.
McCain/Rice is a relatively moderate ticket. (Rice even describes herself as "mildly pro-choice".) If they can hold on to the right wing Republicans, they might pick up votes to the center and left. Even I, who am horrified at the thought of 12 more years of Republican presidents, am concerned that McCain might be more able than Obama to tackle the difficult challenges ahead.
It would be a terrible strategic mistake for Obama to continue to aim his campaign at the left of the party - at rich people who are not vulnerable to economic downturns. Sometime soon he's got to drop his recently-acquired fake southern accent and start talking the way he used to before he entered the presidential race - pragmatically and with insight into important issues. All his empty rhetoric may have been enough to beat Hillary Clinton, but I don't think it will work against McCain.
An aside - the more I think about it, the more I think that Obama must choose a woman as his running mate. (No, this is not about Hillary.) If McCain recruits Rice, then he has both the black and female sides covered, and Obama would need to cover the female side as well.