After R.A. Fisher, John Tukey was surely the most influential statistician of the twentieth century.
Trained originally as a chemist and as a mathematician, Tukey contributed to almost every subfield of statistics and invented several of them. He is perhaps most noted for his contributions to
He also contributed immeasurably to the English Language. In particular, he introduced the terms SOFTWARE and BIT.
His economically most significant invention was the FFT, or Fast Fourier Transform. It has impacted telecommunications to the tune of hundreds of billions of dollars.
He received every honor that a statistician can receive. His most distinguished honor was the President's Medal of Science.
To get a sense of the way Tukey viewed the world, you should read his Sunset Salvo.
More information about Tukey can be found at many websites, including a modest wikipedia article and a much more informative memorial page at Bell Laboratories.