D3, a very powerful, low level charting package, can be difficult to start with. To create just a simple line graph can take a few hours to get off the ground. I found this site which has all a few templates to gets started: http://nvd3.org/ghpages/examples.html.
And, if you're interested in the more advanced D3 visualizations, there's always the Github gallery with some impressive examples:
https://github.com/mbostock/d3/wiki/Gallery.
