The photographer let people choose what they wanted to hold or wear, and presumably how they wanted to stand and smile or not. Some people are very stiff. Some look like they're having fun at the photo shoot. There is an awful lot of looking to the side, which I personally dislike in portraits, but I know it's commonly done. I like the pencil behind McDonough's ear. Desiree Rogers looks stylish and outgoing to me, entirely suitable for the social secretary. On the other hand, Danier Pfeiffer, deputy communications person, looks totally bored.
http://www.nytimes.com/packages/html/magazine/2009-inauguration-gallery/index.html
http://www.nytimes.com/packages/html/magazine/2009-inauguration-gallery/index.html