Call me biased but...
Schuylkill Yards in Philadelphia is a NO BRAINER for
Amazon...
This is basically 7M+ square feet ready to go. What other city can say this?
What other location in the country is ready for this much developable space directly next to two top tier schools in UPenn and Drexel, as well as a large research campus in the University City Science Center, and directly next to the downtown of a major city and major metropolitan region? This is also directly next to highway access in I-76 and 676 to I-95, and 30th Street Station with subway, regional rail and AMTRAK access... which will take you to the Philadelphia International Airport, the Newark International Airport, New York City, DC, Boston, Baltimore, etc. etc....
This site not only connects you to Philadelphia and it's region, but the entire Northeastern United States and beyond. Amazon would have easy access to almost every top tier school along the entire Eastern seaboard for an endless talent pool. That's not even mentioning the sheer amount of Universities nearby in UPenn, Drexel, USciences, Temple, Villanova, St. Joe's, UofDel, Princeton, Rutgers, Penn State, etc. etc.
#AmazonYardsPhiladelphia
http://schuylkillyards.com/gallery.php