The Worldgate Arch would be visible, assuming perfect visibility, from up to 86 miles away before it would become concealed by the earth's curvature. The real world Burj Khalifa is visible from sixty miles away. Worldgate would stand 1,300 feet taller than today's tallest building.
I've been building a city based on World Capitol Project in SimCity to get a better feel for what the street layout, transportation requirements, and zoning demands for such a city might be.
Ultimately, the outskirts of the city are going to be filled with sprawling industrial areas. High rise residential complexes will mingle with high density commerce to provide an inner city which stretches for miles. When the model gets down to finer details, concepts like elevated railways will have to be considered for the heart of the federal and government districts.
This SimCity map (depicting approximately 16 square miles) provides a bit of an idea of what the urban zone and street layout for the inner city will probably look like:
Note the low density industrial areas (farmland). Since this city's history is based partly off of a mixture of Nazi and Soviet cultural ideas (Think Proletariat, Blood and Soil), it seems appropriate that in the inner city, an agricultural/agrarian atmosphere would contrast dense urbanization. Think of big city open spaces like Central park devoted to use as community gardens.