Paul Graham in an interesting analysis says you need lot's of rich people, nerds and a neat place to live to have the right mix for technology start-up nirvana. Read his interesting post here: http://www.paulgraham.com/siliconvalley.html

In the 1st Q 2006, Silicon Valley and Boston did about as much Venture Capital investing as the rest of the country combined. Silicon Valley did 2 Billion; Boston area did 872 Million; NY, LA , San Diego and Seattle area did about 300M each. Philadelphia did under 100M, 20 times less than Silicon Valley and 8 times less than Boston - I knew it felt a little light around here. See the chart here: http://www.pwcmoneytree.com/moneytree/nav.jsp?page=region