Supreme Court ruling aside, it actually seems extremely unlikely that DC residents will be able to buy handguns any time soon. Why? As Rob Goodspeed explains it's all in the zoning. You can't legally buy a gun in DC because there are no gun stores here. And to sell a gun to an out-of-state resident, a gun shop needs to actually ship the weapon to an in-state store that accepts responsibility for background checks, etc. And, again, there are no gun stores in DC. And there never will be gun stores in DC unless some part of the city is zoned so as to allow a gun store. And the city has no intention of doing any such thing.
Most DC residents will be happy with this substantive outcome, but either way it points to the larger lesson that zoning is really important. Most people I know find it idiosyncratic, at best, that I make efforts to familiarize myself with elements of DC's zoning and business license rules. But this is really something that people should do wherever it is they live. A lot of the sort of questions people ask semi-rhetorically about why things are the way they are in Town/Neighborhood X turn out to come down to zoning and business licensing rules that people do well to have some understanding of.
Photo by Flickr user kcdstm used under a Creative Commons license