Recs.
Updated
Specs
Pros
Pro Feature rich and easy to understand
amCharts includes everything a graphing library can provide. From low-level customization to high level complexities, they're all there. Check out their demos page to get creative ideas about using the library on your site.
The syntax is pretty simple and self explanatory too, here's a quick example of a new chart:
var chart = new AmCharts.AmSerialChart();
chart.dataProvider = chartData;
chart.categoryField = "country";
var graph = new AmCharts.AmGraph();
graph.valueField = "visits";
graph.type = "column";
chart.addGraph(graph);
chart.write('chartdiv');
Pro Tons of demos and tutorials, good documentation
Normally coding tutorials won't be required for integrating amCharts thanks to the Live editor. However if any help is required the amCharts website has a tutorial for everything ; be it MySQL integration, real-time data or even adding to Wordpress.