Thoughts on Urbanization

I found this article on urbanization at the Freakonomics blog very interesting. They asked 5 "experts" to comment on this question...

This year marked the first time in human history that more people lived in cities than in rural areas. What problems and opportunities does this present? What effects has it had on our local and global culture? Economy? Health?

Even though Iowa is considered to be a rural state, our future depends on how we think about urbanization.