Lots of bits coming out of the PDC this week. Most of the bits - Atlas, WinFX, WWF (someone had some fun picking that name), run on VS2005 beta 2. But the LINQ stuff requires VS2005 RC1, as does the latest drop of SQL Server 2005. *Sigh* I can't wait til November 7. Really I can't.
Update - Joseph Cooney commented that LINQ does in fact run on VS2005 beta 2. I swear I saw some MSDN page that said otherwise, but now I'm not finding that page, so perhaps I was suffering from an information-overload-induced hallucination. ;)
Update 2 - Duh, found the page that says the VS2005 RC is required for the LINQ tech previews - the main LINQ project
page!