Now that PowerShell cmdlets will replace the stsadm.exe used in SharePoint Server 2007, it can be a little bit difficult to get an overview of the new commands.
A newly published article on TechNet: Index of SharePoint Server 2010 Windows PowerShell cmdlets will help you get this information in a structured way.
There is also a Stsadm to Windows PowerShell mapping (SharePoint Server 2010) available to help transitioning to the new way of administrating SharePoint 2010.
If you ever have wanted to know what new features the Microsoft SharePoint Server 2010 brings to us, you can follow these links from Microsoft.
What's New
From the TechNet site, we have the What's New in Microsoft SharePoint Server 2010 articles.
And from a development perspective we have these MSDN articles:
What's New in SharePoint Foundation 2010
and
What's New in SharePoint Server 2010
Guides
SharePoint Server 2010 Overview Evaluation Guide
SharePoint Server 2010 Walkthrough Guide
Microsoft SharePoint Server 2010 Evaluation Guide for IT Professionals
Microsoft SharePoint Server 2010 Professional Developer's Evaluation Guide
Training Kit
SharePoint Server 2010 Training Kit
VHD
If you want to download and take SharePoint Server 2010 for a test, you can use this VHD: