What are your favorite downtowns?

The U.S. is blessed with a innumerable amount of cities, across a varied geography. Within each city there are central business districts or downtowns, that have an assortment buildings, structures, features, and other qualities. In the celebration of America's downtowns, tell us which downtowns bring the most delight to you or the ones you that are you favorite. Explain what you love about them (e.g.: density, setting, skyline, activities, and so forth) Also, if you have any pictures or links, feel free to post them.>