Multiple Location
Just wanted to put in my two cents worth on the topic. There is a very logical reason for having numerous locations instead of a single super-location (super-tall).
Business Recovery. Should your single super-location be lost to business, or wiped out entirely, multiple locations ensure that you will have:
a) Several operations unaffected by a single incident.
b) Back up locations for displaced employees.
This, of course doesn't speak to the challenges of the black-out in 2003, but that incident was extraordinary.
You would put your most prominent business in the most prominent location with the lesser prominent business lines in satelite locations. This also gives you a presence throughout the downtown core and elsewhere - remember "out of sight, out of mind"