The one I found that I thought was amazing was Snake Oil?: Scientific evidence for popular health supplements. (That link takes you to the interactive version. See the static version here.) On the side is a show me button that flies out a list of uses and types of supplements. Choose what you're interested in to filter the results. The bigger the bubble, the more popular the supplement is. The higher on the chart, the more evidence there is that it works. Notice how many bubbles are below the Worth It line. Remember, the supplements are only good for the conditions listed inside the bubble, which you can see by hovering over it.
What David says about the evidence:
We only considered large, human, randomized placebo-controlled trials in our data scrape – wherever possible. No animal trials. No cell studies. Many of the health claims made by the $23 billion supplements industry are based on non-human trials. We wanted to cut through that.
This piece was doggedly researched by myself, and researchers Pearl Doughty-White and Alexia Wdowski. We looked at the abstracts of over 1500 studies on PubMed (run by US National Library Of Medicine) and Cochrane.org (which hosts meta-studies of scientific research). It took us several months to seek out the evidence – or lack of.
The information is generated from a Google Doc, so when new research comes out it can be easily updated. Very cool indeed. The data has web addresses to the source of the research so you can see it for yourself. It's not just anecdotal evidence.
David also has a chart on caffeine and calories. He even shows how much exercise it will take to work off that large iced mocha you had for breakfast.
He does two interesting charts about politics. The Left vs the Right. A world version and an American version. These are chock full of information.
His 2012 chart is also great. The left describes the believers, the right describes the skeptics, with information refuting what the believers say. Sources are listed at the bottom, and are available in a Google Doc.
His climate change chart shows global warming deniers vs the scientific consensus.
He has many more on his site as well. That's just a few of my favorites.