It is well known that HIV-infected subjects frequently experience hyperlipidemias, insulin resistance, and visceral adiposity, which are known to increase the risk of atherosclerosis. Several cohorts have shown an increased risk of heart disease in people with HIV. The effect of HIV treatment versus HIV itself on the incidence of heart disease is unclear. In this study the investigators will assess the effect on carotid IMT of the initiation of antiretroviral combinations that are known to have a minimal effect on lipids and insulin resistance. We will also assess the changes in several inflammation and cardiovascular markers,as well as endothelial activation markers,and how these changes relate to therapy-induced changes in immunologic, virologic and metabolic markers.