comm552:when my understanding is right, they will ship xna 2.0 at the end of this year and there will be a version for hobbyists and professional developers. don't know if there won't be an express version anymore. the time will tell.
I thought one of the big points of the keynote was that it was only one version? No more Express or Pro, just XNA Game Studio.
I can only speculate here, but I imagine the interface with VS 2005 Pro will mean you can use any *managed* language. So, Managed C++ would probably work. Accessing the XNA assemblies from unmanaged C++ would not work, however.
Also, keep in mind that there is no restriction even now on what language to use. You can use VB, Managed C++, etc. to write XNA games. The only thing you lose is the automatic content pipeline building from the Visual C# IDE. And on the 360, you would need a C# stub to launch your program, but its perfectly possible to write a XNA 360 game in Managed C++ as a separate project, then use a GSE C# project to just launch it, as long as you dont write any C++ code that can't be compiled directly to IL.