Inquisitor:

Which leads me to another anomaly about this race: Senator vs Senator. Traditionally Govenors have made stronger Presidential candidates. What is going on?

I'm glad you asked. The biggest reason why is simply this: money. Specifically, there was a certain large campaign finance reform bill that was passed since the last time a sitting governor was "elected" president. One of the provisions of that was that people running for office who already hold an elective office may transfer funds from their previous-office campaign fund to a campaign fund for another office if it is on the same level of government. Sounds like a tortured explanation, but what it means in simple terms is this: governors cannot transfer funds from their gubernatorial campaign to a presidential campaign because governorships are state offices and president is a federal office.

On the other hand, if one already held a federal office like, say, a Senator, one CAN transfer funds from senatorial campaign war chests to a presidential campaign.

Boy, it sure seems like that campaign finance "reform" bill reformed campaign financing in such a way as to help out candidates exactly like the guy who sponsored it...weird, huh?

But, anyway, the proof is in the pudding: Before McCain-Feingold, the previous two presidents (Bush, Clinton) had been sitting governors. Since McCain-Feingold, all three party nominees (in the not-already-happening-to-be-pr­esident division), Kerry, McCain, and either Obama or Clinton, are all Senators.

But you're right to think it's historically anomalous that we're guaranteed to have a sitting senator elected president this year. In fact, it's only ever happened twice (John F. Kennedy, Warren G. Harding).