It's not often that oil companies are thought of as ethical, but NuStar's Energy (NYSE:NS) treatment of its employees regularly lands it on lists of the best companies to work for. The company pays 100% of its workers' health insurance premium, and even matches 401(k) contributions up to 6%. In addition, the company has a strict no-layoffs policy, and lends its employees the corporate jet in times of crisis. Although it would have placed higher if it was a little greener, NuStar's commitment to its people is truly an example of its ethical policies.