I saw an interesting pie chart identifying the top corporate web servers based on a survey done by Port80 Software...
I may be wrong, but just so everyone knows, this doesn't necessarily mean that Microsoft-based technologies are used more than J2 technologies. These are just the web servers. As I'm sure you know, J2EE requires an app server as well. So, theoretically, one could have an IIS web server with an Oracle or IBM app server driving the content. I still think it's an interesting bit of information, though.