As an asp.net developer, yes, .net is really resource intensive and is basically like a program using a web interface.

By saying that, I mean, it removes the boundaries between a "web" language and a programming language.

Anyway, a good server could probably only host say 20 of these applications. Depending on what they are ofcourse.

My friend created a very sophisticated .net content management system, definately one of a kind and unmatched. He makes a substantial living on it, it's about 800kb / 200,000 lines of code and really does use up resources.

From the sounds of it, the original poster want's to develop with both technologies.

In this case you have to go Windows, what else can he do? He can use open source (3rd party unsupported) software such as ChilliASP developed by Sun etc, but this will get him no where as you have to pay for that license anyway.

This answer isn't debatable and is very clear cut.

If you want access to MSSQL/ASP technologies etc, then go Windows. This allows you to host Win32 based applications as well. So that's a great bonus.

Linux is a great operating system, but it doesn't have the general support of the public (just yet) but it's getting there. I doubt it ever would with Microsoft in full swing, to general consumers they are the only market.

So thus, .net would also be more powerful etc. It is a great technology and tied together with a lot of AJAX, you can pretty much do anything.

Now this was from a developer's point of view if that's what you wanna be / do.