Frank Lloyd Wright was a pioneer of not just "American" architecture, but architecture in general. I have visited Fallingwater (my favorite piece of architecture) and it does not disappoint. I'm not going to waste my time trying to describe it to you... so i suggest you schedule a tour and JUST GO. You'll be glad you did.
One thing that really sets Wright apart from the rest is that he was willing to create more than just a building (a mere shell) to live/work in. Rather, he created a living space that catered to whomever inhabited it. In fact, it seems as though his buildings "nurtured" their inhabitants. His organic architecture compliments our lives AND nature. He was a very, very forward-thinking man and was way beyond his time.
All there is left for me to do is to own a FLW home... (wish me luck)