Another thing, obama probably knows most second terms don't go too well as it is, coupled with the horrifc shape our economy will be in as a result of his policies, and probably figures, like you said, go out while he still has the chance to make millions to do nothing like Bill Clinton does. .
I think most "popular" people - who have always come out shining, always left on top -
I think they might see a potential loss looming, and make a run for the door keeping their pride intact.
The Repubs' entire 2012 message - Let's vote out Obama - you know, the whole anti-Bush thing only reversed, would be neutralized. imagine if, in 2006, Bush had retired for family reasons, appointed Rudy Guiliani VP, then Cheney had retired for health reasons a month later. Two years of President Rudy, and the Dems would have had ZILCH to complain about in 2008... Rudy would have won, piece of cake.
Dems would take away the anti-Obama sentiment in 2012. They'd put up a MODERATE that many repubs love, and Hilary would completely wreck a Palin or Romney in a debate and on experience. Imagine Sarah Palin lecturing Hilary on foreign leaders/policy LMAO... Imagine Romney lecturing Hilary on how to fix the economy LOL...