I found a few interesting visualizations on the Icelandic volcano at http://news.bbc.co.uk/2/hi/8623534.stm. There was a series of 4 images over a span of about 24 hours showing the ash moving around Europe in the 20-30,000 foot range. What caught my attention was the comparisons you are able to make since there are a series of visuals. Plus it is amazing to see how far reaching the effects are. It's easy to see on the news that airlines in Europe are shut down, but the visualization makes it real and more shocking to see the effects of one small island volcano.