In thinking a bit about this issue, I've begun to wonder to what extent residential towers can actually benefit the city. The Ritz is perhaps the most egregious example, but aren't they all to a certain extent simply a vertical version of the despised gated communities of suburbia? Do high end residences filled with high end residents really bring more activity to the street? Is the building foot print large enough to add significantly to the selection of accessible neighborhood amenities?
This comment applies to any tower -- I can think of very few that do anything physically significant for the surrounding neighborhood. Yes, they make for good eye candy from a distance, but what do they do for the man on the street? The one exception regards the office tower, which at least brings a bunch of working and middle class stiffs to the area during the day.