There's been some concern that most of the names mentioned for Obama's cabinet are white guys. In part this is due to an overwhelming focus on Treasury, State, and Defense rather than, say, Justice where several women have a shot, or Homeland Security (Jane Harman is mentioned as a potential pick there). But I do think there will be fewer women in top-level cabinet jobs than many of us would like to see. In part, this isn't Obama's fault. He seems committed to people with deep institutional experience and the pool of such people isn't under his control -- the only plausible female candidate I know of for State, Treasury, or Defense is FDIC head Sheila Bair (for Treasury), but there are also reasons to pick Geithner or Summers ahead of her. Susan Rice is certainly a promising prospect for the future, but right now, isn't experienced enough.
The real test of Obama's commitment to diversity, in all its dimensions, will be how he populates the jobs that could produce a cabinet secretary in 5 years. That's how you really build diversity -- you find people who are smart and have potential and you help them develop it. One encouraging sign is that many of Obama's advisers, who Obama has more discretion in picking, are people like Rice, Cassandra Butts, Valerie Jarett, and Samantha Power.
This is not to say that we should be complacent about the makeup of Obama's cabinet. But we should focus on how well he's doing given the limitations he has to work with.