I think that JSR has created a pretty amazing standard as far as modeling skyscrapers in Lego goes, and the 1/650 scale lends itself well to a good size of model. I created one this past week: Columbus, Ohio's Leveque Tower.
More photos can be found on my Flickr account:
http://www.flickr.com/photos/37034043@N07/
I want to try to do the US Steel building and Tribune Tower next. I'm more interested in doing lesser-appreciated buildings because there are dozens of Empire State Buildings and Willis Towers out there in Lego form. I want to expand the inventory of what is out there, and I would like to see what other people have done in this medium and at this scale.