An old tradition in politics, namely with the first 5 presidents, was that the Vice President would be of a different party than the President himself. This is something we haven't seen in a long time in this country and, in the time of divisive politics, I see nothing but good if one, if not both, of the nominees from both parties did this.
But if Obama really cares about "Change", then he would be wise to list a Republican as his Vice President.
Such an act would not be "treason" to the Democratic Party, but a step forward. It would show that this "change" he seems to want isn't just a slogan but an actual fact. He has already stated he wants a diverse cabinet; why not start at the top?
So let's get it out of the way; I want him to tap Ron Paul for his Vice President. Ron should be president, but in the eyes of many, his policies are too radical a change for America. At the same time, many Ron Paul supporters think Obama is simply using "Change" to get elected and won't do anything to help America once he's elected. People have said that hearing Obama speak gave them goosebumps. To me, hearing Ron Paul talk about economic stimulation, nuclear disarmament, and preaching common sense politics while running as, of all things, a Republican... well, that just plain made me faint!
Ron Paul as Obama's VP ensures a check and balance system of everything. It means that they would limit the government while making sure that everyone got what they needed from it. It would mean that the bickering in the House and Senate would not be too bad as both parties would have allies in the White House at the top. It could, in fact, be the best thing to happen to America in the last 40 years in terms of politics.