I have lived in Philadelphia, Boston and Atlanta. I was pleasantly surprised to find Atlanta's tech scene to be quite a lot further along than Philadelphia. I'm sure Boston's is the most developed but I was only beginning my transition into web development and startups. In Boston I worked in physics research.

I really don't think it has much to do with the "bible belt" as much as it has to do with being in a large metro area and then different metros have different strengths and weaknesses. I mean, Georgia Tech is in Atlanta, it is one of the premier engineering schools in the world. Somehow it has managed to prosper despite being located in the bible belt.