If you are building a company that needs VC funding. Most companies don't.
"Venture Capital is the wrong source of capital for the vast majority of entrepreneurial ventures" http://avc.com/2005/03/dont_take_the_m/
If you aren't looking to raise VC but instead want to be part of a vibrant tech ecosystem, well, that opens up more mid tier cities. For starters: San Diego, LA, Boulder, Austin, Portland, Pittsburgh(?) in the USA.
But, as for the other 80% that's rent controlled, lots of it is pretty dilapidated, almost borderline 3rd world country in some parts. 1% (7k people) of the SF population is homeless and even more are nearly there (despite over 240 million$ a year spent fighting homelessness).
Perhaps the reason people find SF boring is due to the hollowing out of the middle class.
And if you are into oil/gas, Houston. Marijuana, Colorado or Washington. Cars, Detroit (maybe?). Commodities, Chicago. Ag, Kansas City (maybe?). Outdoor experiences, SLC. Building something for Latin America, Miami. Ets, etc.
I imagine there are many other cities that dominate in niches that I'm missing.