>Is Excel an option? I found that it is relatively easy to automate Excel.

I found Excel to be not very scalable for a Web Server. This is not counting any licensing issues, which I'm not sure about. In a web solution I had to do for our Intranet, with heavy use of Excel ,(mostly formulas and results returned in XLS format for the users to display in their browser and be able to manipulate and save, rather than graphics), I found an alternative in SoftArtisans' ExcelWriter. An excellent product, though expensive IMO. It allows you to create Excel files from Templates or with something very similar to the Excel DOM and automation. http://excelwriter.softartisans.com/