WARNING: October CTP VS Bits should NOT be use with the December 2004 SQL Express Release
I just learned that Microsoft strongly discourages us from trying to use the new SQL Express Bits (December CTP) with the Visual Studio bits that shiped with the Beta 2 or October CTP. See this from the SQLExpress Blog:
Important: If you are installing any of the Microsoft Visual Studio 2005 products (such as Microsoft Visual C++, Microsoft Visual C#, Microsoft Visual J#, Microsoft Visual Basic, or Microsoft Visual Web Developer Express edition), make sure you install only the version of SQL Server Express Edition that is included as part of the Visual Studio 2005 setup. Do not use the December CTP release of SQL Server Express Edition in an environment that contains Visual Studio 2005. This December CTP release of SQL Server Express Edition is intended only for users of the stand-alone release of SQL Server Express Edition. (ed. emphasis added)
So exactly what should you use the December release for? Well, testing XM is a good starting place. As for me, I'll be sticking with the October Bits thank you very much since XM does seem to be working OK with it.