Tableau Public is a commercial tool which allows you to create amazing charts out of any data set. They offer also a free version which you can download an use at any time. With it, you have access to all features, except the possibility to save the charts on your computer. However, they do get stored on the Tableau Public servers and you can embed them into blog posts or share them online with anyone. If you are a blogger, crunching and sharing lots of data, you should definitely consider it.
Tableau Public Download Page (requires e-mail address to download & free account to use)