Well... the moment has come, the final version of XNA GSE has been released.
We've got the final doc. at MSDN too, we've got Creator's Club available too for playing XNA Games on XBox 360 (at 49$ for four months or 99$ for a year of subscription)... but...
But I gave a look at the readme,
and as I was afraid of, no support for Windows Vista at the moment
(seems that when Visual C# Express Edition gets support for vista, XNA
will too), no support for Visual Studio 2005 Pro and Team System
editions and XACT tool doesn't work too with Vista ("This issue will be corrected by an updated release of XACT sometime in the first half of 2007").
So, more or less either I format again my laptop and install XP service
pack 2 or I can't use XNA until "somewhere in 2007" if I keep Vista.
And as I'm not willing to format and reinstall again the system, XNA
and I will have to wait a bit longer to get to know each other
correctly...