A major feature that we added to the ADO.NET Entity Designer for Visual Studio 2010 was the ability to create a database based on your conceptual model (a.k.a. "Model First"). To use this feature, start out by adding a new ADO.NET Entity Data Model to your project and choosing to add a Blank Model. Create your model by adding your entities, properties and associations. Finally, right click on the designer surface and choose to "Create Database from Model". For more information, Noam has a great write up here.
One of the core design goals we had while creating this feature was to enable deep extensibilty. We knew that we wouldn't be able to create solutions for every customer and wanted to provide the ability for others to build upon our foundations. Model First is based upon the Windows Workflow (WF) technology and users can customize how the out-of-the-box feature works, add activities to the standard workflow or replace it altogether.
Adi, the main developer of this feature, has just released the "Entity Designer Database Generation CTP" to the Visual Studio Gallery that illustrates these techniques while also adding significant new functionality to the product.
This CTP includes Model First workflows that provide:
Check it out!