These days not much. Additionally, Visual Studio Express is free.
Splashup.com is .NET, IIS, Windows Server 2003 and MySQL. It's never crashed unless I've borked something and it's been through a Techcrunch, Lifehacker, and Digg on the same day.
While this is true for shared hosts, if you want to install on your own machine, run test and dev servers (virtualized or no) or cloud-host your app, there is still a very real cost to windows licenses.
Read up for the part where we discussed Visual Studio Express being free.
The amusing part about the free tools argument is that the cost of tools is such a non-concern in the professional world. I work for large customers on large projects and tools, whether they be Microsoft, Oracle or IBM, no one's worried about that.
Then again, you might be talking about little side projects, my frame of reference is mostly multi-million dollar systems.
Many people on HN are working for or on startups and bootstrapped projects. Implying any project concerned with the licensing cost is a little side project is disingenuous.
Even at large companies, all things being equal, having no licensing costs is a competitive advantage.
