The purpose of this study is to evaluate the safety and effectiveness of the investigational stent CoStar™ Paclitaxel-Eluting Coronary Stent- a reservoir based DES system in comparison to a surface coated DES stent (TAXUS™ Express2™ Paclitaxel-Eluting Coronary Stent) in the treatment of single-vessel (one blood vessel) and multi-vessel (two or three blood vessels) coronary artery disease.