Well, if you're talking about chart junk and aesthetics, I am led to believe that you are talking about casual info vis(information visualization) - infographics, info-charts,etc. The term aesthetics means two different things to me depending on the context in which it is used. If used for casual infovis it is subjective, how beautiful the visuals are, how well they are laid out, how crisp is the content.
The term chart junk has its origin (debated) in Tufte's work. According to tufte, any graphics, visuals, etc, which are not conveying information are junk. And by that definition, many of the 'beautiful' infographics are filled with chart junk which only add "aesthetic" value and no actual information. Tufte is an extreme example since, he was so pro real estate utilization that he questioned even the necessity of the graph's axis lines. You can read more about his philosophy in his work http://www.edwardtufte.com/tufte/books_vdqi.
When talking about serious information visualization (which I am guessing, you're not) you follow taxonomies and grounded research in different areas like information representation, interaction of the graphs & charts, the color selection. A couple papers if you have access to academic journals.
T. Skog, et al, "Between Aesthetics and Utility: Designing Ambient Information Visualizations", Proc. of InfoVis '03, pp. 233-240.
J. Fogarty, et al., "Aesthetic information collages: generating decorative displays that contain information," Proc. UIST '01, Nov. 2001, pp. 141-150.