As for unbuilt Gehry proposals - I guess I have mixed feelings about the Progressive Insurance Center planned for Cleveland in the late 80s.
The good: it would have brought 3,000 employees of Progressive into downtown; it would have incorporated some major public art pieces, including an Oldenburg newspaper as the crown; it would have bridged the railroad that runs along the lakefront; it would have been the second-tallest after Key Tower at 858 feet. The bad: the proportions are a little ungainly; it would have really unbalanced the skyline - for the most part, Cleveland's skyline has a "pyramid" silhouette and this would be a sore thumb. Part of me says it would have been kick-@ss; part of me thinks there might be a more appropriate design for the site:
It would have been built just above and to the left where you see the domed structure on the lakefront (center-right of the photo - the IMAX theatre at the Great Lakes Science Center):