The overall purpose of this research is two-fold. First, the two smoking cessation medication treatments with the strongest evidence of effectiveness have never been directly compared. This research will determine how these two treatments compare in effectiveness in a head-to-head trial, and which types of smokers benefit most from each. Second, much of the data on smoking and health come from studies from many years ago. Today's smokers differ from earlier smokers in many ways that could influence the impact of smoking on health (e.g., weight, sex, diet, socio-economic status); the proposed work will determine how smoking cessation affects cardiovascular and pulmonary health in today's smokers.