This panel brings together researchers who have been pioneering quite different approaches to visualization research by integrating evaluation and knowledge of visual design into their work. The panelists will present their views and experiences in using user studies for quantitative evaluation of methods, in integrating the expertise of visually trained designers into the development of methods, and in exploring the parameter space of visualization possibilities using "human-in-the-loop" experiments. A goal of the panel is to encourage a lively and stimulating discussion by presenting challenging but highly contrasting ideas. The panel will follow the usual pattern of short position presentations, taking care to leave ample time for audience interaction, questions, and comments.