Good resource on property tax issues
-- Property Tax webpage, Lincoln Land Institute
While the report is "biased" in that it believes that residential and commercial property should be taxed equally, it looks at the high and low cities in each state and the District of Columbia.
DC compares quite favorably to most major cities. In this region, while the overall tax "burden" maybe a bit higher than in Northern Virginia, it's actually much lower than people think--e.g., property taxes in DC are lower than in Maryland, especially compared to communities that have both a county and city tax (e.g., Rockville, Takoma Park, Mount Rainier, etc.).