For some reason, most .NET devs that I run into insist on using closed source applications for everything they do. I have no idea why. I guess it's a culture thing. That's why I love it when a mostly ASP.NET fellow starts using something open source, like Subversion source code control. All the tools are in place to do what you need, the TortoiseSVN windows explorer plug-in, the Ankh Visual Studio plug-in. It's all there.
Plus, I've really fallen in love with the concept of a hosted subversion solution. For me, I host my own at my provider. But for my side projects, its great to be able to access them from multiple computers. If I can get to the internet, I can get to my project code.