One of the most widely accepted alternative theories of world inequality is the geography hypothesis, which claims that the great divide between rich and poor countries is created by geographical differences.
This article is an excerpt of the forthcoming book "Why Nations Fail" that should serve as an ideological counterweight to the book "Guns, Germs and Steel." The authors argue that the wealth of a country is most closely correlated with the degree to which the average person shares in the overall growth of its economy, meaning that political institutions are more relevant to economic success and development than physical geographic resources.
For more on this upcoming book and it's hypothesis see this NY Times review: http://www.nytimes.com/2012/03/18/magazine/why-countries-go-bust.html
Via Seth Dixon