A directory containing a Visual C++ solution contains a lot of files. Some of these are essential to the solution, like the source files. Most of the files are generated by Visual Studio to help with Intellisense or as a memory dump or during compilation. These are not essential.
If you are using a version control system (like Mercurial), you only need to checkin the essential files. These are:
Solution File (.sln): Contains information on the projects contained inside the solution.
Project Files (.vcxproj in Visual Studio 2010 or .vcproj in Visual Studio 2008 and older): Contains information on one project.
Source Files (.cpp, .c and .h): Source files that belong to the solution.
Resource Files (.rc): Cursors, icons, bitmaps and other UI elements of the solution.
Filter Files (.vcxproj.filters in Visual Studio 2010): Stores the hierarchy of files of a project, as displayed in the Solution Explorer.