"Oil not only creates very few jobs, it also destroys jobs in other sectors. By pushing up a country’s exchange rate, the export of oil distorts the economy. “Oil rents drive out any other productive activity,” Karl says. “Why would you bother to produce your own food if you could buy it? Why would you bother to develop any kind of export industry if oil makes your money worth more and that hurts all your other exports?” The most successful societies develop a middle class through manufacturing; oil makes this extremely difficult." (Thanks D.)
A looong article on Chavez and his oil, in the NYT.