I have long been an avid reader of The Guardian (albeit in its online incarnation, except for Saturdays when you can't beat stretching out on a sofa with the oversized supplements), and have been impressed with their skills at using data to uncover hidden truths that are often concealed behind complexity.
Today, I've stumbled upon not one but two exemplery data visualisations from The Guardian which struck me not for their aesthetic value but for the simplicity of their message.
The first one http://www.guardian.co.uk/world/interactive/2012/nov/22/eu-budget-interactive-money relates to the EU budget and allows you to interact to select your country of origin to see how much you personally contribute to the EU budget (average for the country, not YOU personally!) and how much you receive. . I never realised how much cash Poland receives from the EU coffers!
The second http://www.guardian.co.uk/news/datablog/interactive/2012/nov/22/wages-map-britain is again financial data, but this time looking at average earnings in the UK. I was shocked to see that there only 4 local authority areas in which women out-earn men (funnily enough, one of them is mine!).
What these two visualisations prove is that the key to impact and insight is simplicity. To my mind, it is one of the hardest things to achieve in visualising data. I recall a diagram from Andy Kirk on his Visualising Data course in which he talks about the journey of the data/message getting from the visualisation to the brain of the viewer, and how that journey needs to be as direct and unimpeded as possible. Its something I strive for (though don't always achieve), and something which The Guardian has become very adept at.