Jim,
Good point and post above about flying around Washington, DC and Baltimore, MD....
I do it routinely for work, and...
...call me what you will, but I would NOT even THINK about doing it without the aid of a GPS with moving map display.
The radio traffic, airline and helicopter traffic, and overlapping TFR's, SUA's, MODE C veils, with CLASS B airspace inside the SFRA and FRZ has us on our toes here during single-pilot VFR ops. I have gone back and forth inside the DC Beltway area close to 150 times now. Navigation to the tenth of a mile is imperative in many places....and in that urban sprawl, a lot of things tend to look alike! Navigating by dead-reconing and pilotage over urban sprawl is as difficult as doing it over wide open forrest. Freq changes are constant and we often have to monitor two radios at once. It's challenging, but anyone here could do it with a bit of mission prep and focus!
While I love just having a sectional out and flying for fun, it is ALL BUSINESS in that area! My IFly is "essential equipment" in those areas. That's just me, others may feel perfectly ok without a GPS in that mess, but you are betting your ticket if you do...
Mike Marra, N714AJ