I love data visualisation and to spread that love I thought we could share our favourite examples of data visualisation:
Chess moves http://turbulence.org/spotlight/thinking/chess.html
Chris Harrison's Visualisations http://www.chrisharrison.net/projects/visualization.html
I especially like the bible and Wikipedia visualisations.
If you're interested in creating your own visualisations a good place to start would be to check out processing.js (http://ejohn.org/blog/processingjs/).