TBH I'd take this gigantic block of normal Parisian apartments, plop it somewhere like Woodley Park, and instantly transform an entire DC neighborhood from single-family houses to real city:
Google Maps
But if that's a bit too far outside the spirit of the thread and I have to stick with a skyscraper, I'd take Bryant Park's American Radiator Building and put it in Silver Spring, Maryland, which would give the DC area a landmark skyscraper, be super visible from a lot of different places, psychologically legitimize Silver Spring, and change the discussion about skyscrapers in the DC area.
[url=https://en.wikipedia.org/wiki/File:NYC_-_American_Radiator_Building.jpg]Jean Cristophe Benoist via Wikipedia[/url[