Gapminder

Gapminder is a interactive and online tool to make graphs. It´s a very good tool to design interesting graphs.

Hans Rosling was its founder and now he makes funny presentations around the world about data and the socioeconomic trends (see this video).

The only negative thing is that you can't upload your own variables. The good thing is that the number of variables available in the tool is pretty astonishing: 519!