Primefaces seems good, I tried using JFreeCharts with Richfaces a year back and had a tough time. If a JSF library like Primfaces gives you out of box charting functionality, that is the right way ahead. Thanks Robert I will give it a look too.
I am suprised Richfaces has not caught up on Charting yet.
you can also use highfaces (http://www.highfaces.org). HighFaces wraps around HighCharts and supports instantly turning any Collection into a chart without having to write any JavaScript or JSON yourself. It further provides full integration into the JSF-AJAX queue for e.g. clicks on points.