When you say you are considering moving, "for better opportunities in the startup world," what opportunities? Are you looking for a job? Starting your own company?
I'm speaking in terms of founding and growing a startup.
You can do that anywhere- do you need capital? Then yes, SF has more (and easier) sources to find for capital. But really if I were you I'd build the thing first- you can always move later if you have to.
The biggest thing about building a startup is GET STARTED :)