Boston or Silicon Valley?
mhidalgo: I know the post is whether to choose from Boston or SV, but I see your from NY. I been around the NYC startup scene for while and there a bunch of activity here and it only has increased since Wall St. decided to die.  Brooklyn and Manhattan have a bunch of startup opportunities, even some startups from Ycombinator are located here like Buglabs and Frogmetrics. Not to mention organizations/meetups like Jelly ( coworking started in nyc), Meetup.com's ( located in nyc as well)NYC tech meetup, and http://www.nextny.org/. Obviously if you feel the need to move to Boston or SV I understand completely given there status in tech world but don't overlook your backyard as well.