The Martin House is an excellent example of Frank Lloyd Wright's design genius. (It is one of the reasons I myself went into architecture.) It may seem surprising at first that a simple town like Buffalo would be home to a Frank Lloyd Wright work, but Buffalo has more unique architecture then you might think. The Martin House is under some renovations as of 1/06, but it is still open for tours. Check out www.darwinmartinhouse.org for tour information and updates on the renovation work.
Also of interest to anyone who appreciates Frank Lloyd Wright is Graycliff. Graycliff (nicknamed "Wright on the Lake") was the summer home of the Martin family and is located at 6472 Old Lake Shore Road in Derby, NY (about 30 from the city). Graycliff is also under renovation. Check out graycliff.bfn.org for more information.