Presumably the same things that makes an area attractive to artist and hipsters makes it attractive to start-ups: Cheap spaces to work and live. At least if you are bootstrapping, that is a big deal.
I come to the startup world as someone who's also a musician - and music will always be my first love - and I don't think the two worlds are necessarily that far apart. Obviously not everyone wants to hang out at cool gigs and art galleries, but generally startups are started by people who are younger and more energetic and like to hang out in those areas where the artists are. In my experience those areas are normally the fun parts of town.