Lists of big cities:
- a survey on financial centres says London, New York, Singapore, Tokyo are the best/most popular: http://www.longfinance.net/images/gfci/GFCI21_05_04_17.pdf (note that the ratings for San Francisco on down go down by 1 or 2 points at a time for awhile, unlike the gap between San Francisco and Tokyo, which is 16 points)