在Windows Server上部署的最佳免费Web框架？

If you are starting to develop a new web application from scratch and the only two requirements you have is that it will be deployed to Windows 2008 Server and that standard ASP.NET incl. VS2008 doesn't cut it (doesn't matter why, let's say it's the license cost, you won't be hosting Windows 2008 Server yourself). Which web framework would you choose under this circumstances?If you are starting to develop a new web applic