D3 + Python

A simple visualisation of London's housing market data, viewable at http://www.sjwhitworth.com/files/d3/londonhousingdata.html
To run locally, run londonhousing.py to generate the JSON needed for D3 to do it's thing.
Then, run a HTTP server locally via Python - sudo python -m SimpleHTTPServer 3000 & - and browse to londonhousingdata.html on your filesystem.
You must have topojson installed for the conversion to work - see here for how to install. http://bost.ocks.org/mike/map/