I love self-explanatory graphs. The one that you just look and intuitively understand what it is about. This desire is deeply rooted from my years in PhD, where I had to produce many graphs of experiment results and at the same time I had to understand many graphs other graduate students have produced. The best tool I knew for such scientific publications was LaTex.
Anyone who's interested in data visualization on web, come to meet d3.js
It is equipped with all the possible functions to help in making self-explanatory graphs. There are literally hundreds of examples that will help you build beautiful and insightful graphs on the site.
Here is my example: 80/20 Rule in enterprise level CAD software.