Jon Udell had a really interesting post detailing the number of Virtual Machines that reside on his various computers. I agree it would nice to see Sun increase its support for development of other languages based on the Java VM. I attended JavaOne in 2004 and there was a session on Groovy. I’m not sure that Groovy has been widely adopted and that Sun is willing to invest in taking the Java VM into the multi-language arena. Microsoft on the other hand seems to be ready and able have .NET be the multi-language VM of choice. I would think that Microsoft would be the choice to win the non-windows .NET VM competition. Thinking about it a bit more there are a large number of people that would prefer Mono just because its not directly from Microsoft.