He measures Los Angeles as the most bohemian city in North America and the five least bohemian are the following:
3. New Orleans
The lists continue at the link, along with a very interesting discussion. I'll accede to some version of this more-scientific-than-my-intuition list, while noting that my picks were different in part because I restricted my attention to much larger population centers. Florida also remarks that Stockholm measures as quite bohemian, while I wish to note I'm familiar with the Goth culture of Santiago, Chile but not so impressed by it as true bohemianism.
Addendum: Here's the start of Florida's definition: "The index charts the concentration of working artists, musicians, writers, designers, and entertainers across metropolitan areas." I had something in mind more about the "feeling of the place," so I see L.A.'s "Downtown" as quite bohemian in spots but the city as less bohemian overall than Florida's index will indicate.