Let's take a look at another web site that offers visualizations. We'll use IBM's ManyEyes to create a bubble chart showing the number of jobs in each job title in the city government.
To build this, we'll use a roll-up and a sort to get the count of each job title (ie., the number of police officers, number of firefighters, etc.), download the results to a spreadsheet, copy the ones with more than 100 people in them, paste them into ManyEyes, and have ManyEyes create the bubble chart. Here's that visualization:
You can publish this visualization on your own web page, too. See the Results #7 entry for an interactive example.
ManyEyes has more styles of visualizations. Once your data set is loaded, it's easy to try others.
Ready to watch? Here's the YouTube video