I’m probably the last quantitative person on the net to discover the magic of Google Charts. The API is completely URL-driven, so all you have to do is fill in the blanks to get presentation-quality charts like this (from an ongoing project and completely devoid of context):
The URL for the chart above is here (line breaks inserted for readability):
http://chart.apis.google.com/chart?cht=p&chd=t:28,23,18,8,7,7,7,2
&chs=450x200&chl=DC%20Action%20(28%)|DC%20Knowledge%20(23%)
|DC%20Join%20(18%)|AC%20Expr%20(8%)|AC%20Knowledge%20(7%)
|DC%20Expr%20(7%)|AC%20Join%20(7%)|AC%20Take%20Action%20%20(2%)
&chco=ff0000,00ff00,0000ff
The developer’s guide is ridiculously easy to follow. For me at least, it really takes a lot of the headache out of whipping up data visualizations. This is definitely my second-favorite new toy of 2008.