And the streets were paved with glass...
Here's an interesting Seattle Times article I saw on News.com about the practical side of the quest for more bandwidth. In Seattle (and probably many other cities), everybody wants fiber-optic cable, and laying cable means digging. The article gives an example of a street that was repaved in 1998, and has already been dug up twice, and will probably be dug up again in the next year.
The area immediately under the streets has become so full that in many places, new cable runs require digging by hand to avoid severing existing cables. The city may eventually have to build concrete tunnels under the streets to hold them all, and even that might not be enough.
Personally, I think they should just drop all pretense and start laying the fiber down on the surface of the street. Oh, I know what you're thinking: "But then the fiber would be ruined the first time a car drove over it!" Well duh, that's where the hover-cars come in. Geez, do I have to think of everything? Heh heh.