One of the clear cuts on this campaign is that McCain's effort is all about biography, whereas Obama's has been all about political strategy. The McCain camp has been woeful on political strategy. Obama's biography, although interesting, isn't as captivating as McCain's.
This is not a biography year. This isn't about what you did when you weren't President, it's about what you'll do, and how you'll get it done, if you are President. To that extent, all these expected efforts by the McCain camp to blast Obama's biography are likely to fail as long as Obama continues to work the "what the next President has to do" territory.
And to be honest, maybe we're seeing that NO year is a biography year for electing a President. When was the last time a candidate for the office won that had the most compelling - and impressive - biography? 1988?