Not necessarily the most "world renowned," because those are only few (NY, Chi, LA, San Fran). Where exactly would you want to live? What city do you believe has the most admirable attributes (least crime, pollution, best educational system, health care, etc)? Of course most of us have not been to or even know of the standards in some of these world class cities, so feel free to opine.
New York
San Francisco
Los Angeles
Washington, DC
Boston
Seattle
The TC
Philadelphia
Denver
Other
New York
San Francisco
Los Angeles
Washington, DC
Boston
Seattle
The TC
Philadelphia
Denver
Other