Here is a report by Brookings' Alan Berube on the 2010 census and what these data say about U.S. metropolitan areas. He documents "demographic convergence."
This make sense. Income, ethnic and class distinctions aren't what they used to be and they are not as easily plotted on city maps as, say, fifty years ago.
There are employment centers and sub-centers all over the place. Many of the traditional downtowns offer residential variety. Commuting is more complex than ever. San Francisco is a dramatic example. Its former "bedroom" communities along the Bay Area's penninsula are now the places where many who now live in SF go to work.
The 2010 census data show once again that it's an auto-oriented world. Auto-oriented is a much better descriptor than "sprawling." It describes most development in most U.S. metropolitan areas. "Central city" vs. "suburb" are dusty labels still used in academic literature, but they are fading as useful descriptors for most others.