I've always thought that the WTC site might be a nice spot for Frank Lloyd Wright's Mile High Building.

It's so thin that it probably doesn't have that much office space, and the design is very classicly modern and would fit in perfectly with the New York skyline (except that it would be 4 x the size of anything else). Plus we could always use it as a space elevator....

http://pes.eunet.cz/architek/0414arch.htm

(I'm afraid that this page is in Czech, but it was the only good picture I could find of it)

Gaudi was comissioned to build a Hotel on the site back in the olden days

http://www.paranoiamagazine.com/gaudihotelshort.html

P.s. sorry the links to tin-foil beanie territory but it was the only page i could find about it on google