I came across an interesting article on the New York Times site that talks about how they used Amazon EC2 and S3 to help make their articles from 1851 -1922 available to the public online.  There was a total of 11 million articles.  They had to take sometimes several TIFF images and scale and glue them together to create one PDF version of the article.  They used 100 EC2 instances to complete the job in just under 24 hours.  They started with 4TB of data that was uploaded into S3 and through the conversion process created another 1.5TB.