I did an experiment.. set up 2 site with diff location. One is hosted in US, one is in my country. Then I posted 20 articles (drip feed of course). Then I buy the exact package (quite a diverse package, include web2.0, social signal etc) after 2 weeks, the first one rank well in google.com, while the second one favor google.com.id damn, now it's clear where should I host, server location is a huge seo ranking factor!! Maybe this is not 100% accurate, because they will be slightly diff btw 2 sites, probably in the article quality or kw etc..