The Davis Square area is certainly very nice, I lived in it for the last half-dozen or so years of my stay in the Boston area (late '80s-very early '90s), but there's no way a family is going to fit into a $425/month apartment that's anywhere near it.
For the criteria of taxes, cost-of-housing, congestion, state debt and general cost of living the Boston area is just plain bad and as far as I know getting worse.
Commuting from southern New Hampshire isn't a great option either, the cost of living there is still pretty high and unless you can do it off peak it's very congested. And there are a lot of tasty startups in Cambridge, you'd need to have a commute to there be practical.
While I believe there's a big separation from the Boston area to the next largest startup areas in the nation, I think Daniel's criteria that rule out SV also rule out it, although not as strongly.