> I recommend testing on Windows Vista and Windows 7, with Visual Studio
> versions 2005, 2008 and 2010. You will also, obviously, need to test
> against multiple versions of CMake based on the versions ROS supports. 
We are using Windows 7 64bit, Visual Studio 2008 (32bit) with SP1 and
latest cmake (currently 2.8.2).

Vista (32bit and 64bit) and Windows 7 (32bit) do not make any difference
to the compiler so you would just have to decide for one OS (I would
recommend Windows 7 32bit, which is the mainstream right now). I also
would recommend VS2008 (32bit) with SP1 which is the most stable VS you
can get at this time. Take the latest cmake version.

I think you can skip testing with VS2005 as this product comes to EOL.
VS2008 is currently used by most people.