Many of the Dems are wanting an Obama-Clinton ticket. A lot of people feel that by losing a significant amount of Clinton supporters will result in another November election loss.
Bob Beckel is one of those people. His entreaty is a bit subtle in some ways. But make no mistake, it's what he wants and what many other traditional Dems want.
Others don't want it and are openly against it. They appear to be be thinking and hoping for Edwards, and there's even a t-shirt being offered as a means of displaying this wish.
As for McCain, there many that I think he could pick, many that would compliment him. He needs a younger conservative to help reattract the base.
One of the many possibilities has been hinted on Human Events. Although he has his detractors in the state of Indiana, he has reduced taxes, cut spending, and successfully eradicated a huge deficit that was left to him by 16 years of Democratic rule. You can read the article to see what this man has accomplished in four short years.