These guys do nice work. Here, and in earlier posts (one reference at the bottom of the page in particular), they provide very concrete advice on how to improve specific charts including column charts, treemaps, etc. They also have open source software to try out for treemaps (need to download and try).
Chart Makeovers, Fed IT Dashboard edition: Juice Analytics
Idea: DataViz Makeovers (with appropriate attribution of the idea to colleagues at Juice Analytics)
Interactive longitudinal map of Milestones in the History of Thematic Cartography, Statistical Graphics, and Data Visualization http://datavis.ca/milestones/
These guys also do an intriguing Gallery of Data Visualization where they laud and criticize the best and worst of statistical graphics: http://www.math.yorku.ca/SCS/Gallery/index.html
Idea: Create a similar gallery with critique and praise of graphics from evaluations
Idea: Create an annual award for best representation (interactive and non?)
Idea – Contribute to and update relevant wikipedia pages such as those on:
One idea to support the data visualization and reporting community would be to hold a critique week where colleagues would provide positive peer-critiques of example visuals.
Ultimately, best practices might emerge from the peer critiques.