DC has a fight on its hands apparently as a 37-mile streetcar system was ready to start digging up its streets for the first phases of what the Washington Post rightly suggests is about "connecting neighborhoods rather than merely moving commuters."
Opponents, which are many and not of the inconsequential or disorganized kind, point to a longstanding ordinance banning any overhead wires for utilities, all of which are buried. As Dallas and Fort Worth both move forward with planning for streetcar lines, this might be another element to throw into the equation.
You'll notice some developments around the DFW area such as Addison Circle and Legacy Town Center where the utilities are underground, and it makes a significant difference. For the contrast, take a stroll through the State-Thomas neighborhood in uptown Dallas, where burying the utilities was optional for the developers. The patterning of overhead vs underground is helter skelter and disorganized.
Greater Greater Washington has a new post up suggesting DC at least undergo a study to determine the exact cost/benefit differential for underground power instead of a pole and catenary system typical of most streetcar systems. They also include a picture of Bordeaux, France with their system implemented in 2003:
Bordeaux with ground power:
Bordeaux with catenary system
I have never been a big fan of the system of wires cluttering streets in order to operate streetcars. But, while it is easy to show pictures of a clean (no wire) systems, if it is too cost prohibitive, in my opinion it isn't worth throwing the baby out with the bathwater.