Have you started to play with this yet?  I am just now getting some time to explore.  Tonight's find is the modeling project type and the modeling objects.  Being the big language geek that I am, I just love ORM-like abstraction layers.  Here's some intriguing stuff I found while adding a layering diagram to a modeling project template type.  Note that in addition to the traditional 3 or 4-tiered model, we've also included MVC.  Also there is a LayerDiagram Explorer.  Ah there is just not enough time to play with the new toys, now is there.  What have you 'found' in the recent VS2010 CTP that you like?  I'd be interested to know.

Layering Project in VS 2010 

Download details: Visual Studio 2010 and .NET Framework 4.0 CTP