One thing that I'd like to remark on, since I keep thinking stuff like this when you post "Honeymoon with Switzerland" comments, is that Switzerland is a very old country, where people have been living in the same settlements for centuries, and that these settlements developed during a time when rapid transit meant you were riding a horse.
America is a young country, created by colonization and subsequent expansion. When most of the aggressive expansion happened, the development of the train was happening simultaneously, and a culture developed where people from Boston would think little of taking a train to Denver to apply for a job. After that, urban expansion took place, simultaneous with the development of the automobile and the highway system.
I think Shoshona is right that DC proper is That Way, but DC was explicitly designed by a European to emulate the Great European Cities, and it's kind of an exception to the general (accurate) rule of America = sprawl.
But, I think that given a few hundred years, America will be a little more comfortable with itself, and not so excited about how much space there is, and that the Big Urban Centers, like DC and New York, and LA, and all like that, will be Sprawling Shopping Messes, but that the small towns (Roanoke is beautiful, for example) won't need to sprawl so much, and the downtowns will be jewel-like in their clarity of social focus, and the suburbs will be pleasant and the trees will drip treacle.
Well, okay, I'm not at all sure that I actually think that. But it's a wonderful little vision, ain't it?