Don,
It would be great if you could do it before the contest end. The two most recognizable skyscrapers in Boston are the Prudential Tower and 111 Huntington, they are right next to each other. This shows both of them:
http://en.wikipedia.org/wiki/File:111-Huntington-Ave.jpgThen the Zakim bridge would be a really great addition after the skyline that would really make it uniquely Boston. There are pictures of that here:
http://en.wikipedia.org/wiki/Zakim_BridgeThanks!