As you probably know, Visual C++ projects in VS 2010 use MSBuild to build. That works fine when you have Visual Studio installed, but can you build your C++ stuff without Visual Studio installed? One could build C#/VB projects with only .NET Framework installed, and prior to 2010, to build VC++ you only needed Windows SDK (that included headers, libraries, compilers and other goodies). So what is the story in 2010?
It turns out the story is similar in 2010 - you will need to have Windows SDK (for C++ specific bits) and .NET Framework 4.0 for vcxproj files. The only fly in the ointment is that Windows SDK is yet to be released (with target date somewhere in June 2010), so for now to build your C++ projects you will need to have Visual Studio installed.