The top 5 Republicans President Obama didn't want to face in 2012 election

5.  Bob McDonnell - governor of Virginia. Good pol and would be difficult for President to exploit his major weakinesses: lack of experience and foreign policy
4.  Bobby Jindal - governor of Louisiana. A person of color who could match wits with the President who had a record of accomplishment.
3. John Thune - Senator South Dakota. Made for tv candidate similar to Mitt Romney without the flip flops but comes with consistent conservative record and  giant-killer history of defeating  Senate Democratic leader Tom Daschle.
2.  David Petraus - military leader.  If he declared as a Republican, identified with the best of the tea party and Occupy Wall Street, while respectfully criticizing the President; he'd be tough to beat and to attack.
1.  Marco Rubio - Senator Florida. His potential to excite conservative base and cut into the President's latino voter base, in addition to  potentially taking Florida off  the board.