First, if you haven’t seen it, there is a fascinating presentation by Hans Rousling (at TED conference) of data on issues like child mortality, life expectacy, GDP, Internet use, etc. His interactive software is available at Gapminder and here. You can chart variables by nation over time like military budget, phone usage, doctors per capita, urban population, percentage of women in the paid workforce, etc.
Secondly, IBM has some interesting new Alphaworks tools that let you visualize dominant themes. Click here for a visualization using tag clouds of the House of Commons debate about Iraq War [IBM calls this Many Eyes]. Larger words are more commonly mentioned words. You can select in the radio box whether to sort by 1 word or two word phrases. You can use Many Eyes to upload a large amount of text and find and visualize dominant themes.