Prepping for civil unrest is beginning to take on a new urgency, in my opinion. Over on Blog O'Stuff, I've posted here and here some pictures of the Occupy Oakland and Occupy Philadelphia crowds, respectively. When you have persons like the Mayor of Oakland and the President of the United States openly voicing support for communist revolutionaries within our borders, it isn't a big stretch to see this spreading and becoming more violent.
IMO, ff you live in an urban area you should be prepared with sufficient food and water to last out a week's worth of rioting at a minimum, along with fire extinguishers, first aid supplies, and the means to defend yourself and your home.
Don't get caught with your pants down.