Many factors contribute to the design of a successful E-Commerce website. This paper discusses the importance of integrating fundamental usability and design elements, such as Gestalt principles, Fitts' Law, heuristics and affordances with newer constructs, such as social presence, social networking, trust, and both online and offline communication. A case study is presented which compares Heuristic Evaluation (HE) with usability testing (user experience test and eye tracking). Both methods were used to evaluate the impact of usability and social and trust elements on four e-commerce websites. Eye tracking was also used to assess the impact of social presence in one e-commerce website. The results reveal the importance of these elements for E-Commerce website design. © 2011 IEEE.