I agree that Barack Obama is an ENTP. You get this sense of contained energy from him, like it's taking all his discipline to present the sober image required of a US President but what he really wants to do is run around and really throw himself into the job wholeheartedly.
The ENTP configuration also explains his charm and charisma. ENTP types have Fe as their tertiary function and may use it a lot to in service of their dominant intuition: to basically "win friends and influence people". They can be very charismatic and persuasive when using this function, with a certain boyish (or girlish) charm.
Obama is particularly adept at oratory, I'd guess that he has worked very hard to develop his Feeling function in an attempt to balance the cooler, more remote attitude of his Auxiliary Ti. This is why he appears ENFJ-like to so many people.
IMHO, Obama's innate type, and his seemingly high level of personal development, makes him uniquely qualified for the difficult tasks ahead of him.
As for Michelle, that interview was revealing, but not nearly enough to accurately guess her complete type. The I and J are pretty obvious, but the other two letters are open for debate. I'm currently torn between ISFJ, INFJ and ISTJ.