Would VS10E be ok?
would the installation of "Qt libraries 5.0.0 for Windows (VS 2010 406 MB)" require a registerd version of VS10 or would VS10E be ok?
Express is fine for coding and compiling. You won't be able to use the Visual Studio Add-In, however.
Strictly speaking, you do not even need Visual Studio. The compiler from the Windows SDK is fine, and integrates quite well into QtCreator.