In short, the GOP primaries could decide who gets to be the Landon/Goldwater/McGovern/Mondale of 2012 if most things go right for Obama -- no foreign-policy blowups, no personal scandal, and some well-received reforms of the economic and political systems.
I still remember quite clearly back in 1992 a SNL skit parodying the Democratic primaries - who gets to be the guy to lose to George H.W. Bush in the fall? IN the skit, everyone was contending to not be the nominee.
Things change, and it is unwise to count your chickens too early...
This seems so obvious that it can't be original: there is no "typical Presidential election" in American history. Every one of them is different (except arguably 1952 and 1956). Every President is different, and the conditions under which every President wins is different.
I can't predict that there won't be a strong third-Party challenge in 2012-- yet.
A nasty situation is underway in North Korea. Who knows what resolution that will have? I can imagine the optimum (China, Russia, Japan, the US and the Republic of Korea are able to establish a definitive solution to the Korean Conflict which has never had any resolution beyond a cease-fire). All reasonably-wholesome endings to this mess involve Kim Jong-il either dead or in a mental institution.
I have more confidence in Obama than I could have had with Dubya.