I'm excited with the new changes and functionalities that Windows 2008 will provide to the enterprise and hosters. To mention some of these features, Windows 2008 provides a minimal version of the OS (Server Core - the most efficient Windows version ever), expansion in the capabilities of powershell and how the server can be administered (you'll be able to obtain a script for almost any correspondant UI control or task), additional HA features are incorporated/enhanced into Windows Server (failover clusters, Network Load Balancing, dynamic hardware partitioning, robust storage options, and advanced machine-check architecture), enhanced OS-virtualization mechanism to consolidate and optimize the resources in the DataCenters (Hyper-V), let's don't forget IIS 7.0 and its additional features (PHP integration, security enhancements, larger no. of web-sites supported per server).

If you want to know more about these features, check out the following set of online videos which presents the capabilities of Windows 2008:

Windows Server 2008 Deployment Overview - Michael Niehaus, Tim Mintner
The 10 Most Important Things About Failover Clustering  - Jim Teague
Power Management: Windows Server - Stephen Berard
Dynamic Partition: Windows Server - Davis Walker
Windows Server Longhorn - Iain McDonald
Windows Server virtualisation - solution scenarios - David Hitchen
Windows Server 2008 Kernel Advances - Mark Russinovich
Active Directory Domain Services in Microsoft Windows Server 2008 - Stephanie Cheung
Virtualization in Windows Server - Mike Neil
Managing Windows Server 2008 with Server Manager - Dan Harman
Using Group Policy with Windows and Windows Server 2008 - Mazhar Mohammed, Derek Melber
Microsoft.com: Employing Windows Server 2008 and Internet Information Services 7 - Paul Wright, Brad LeRoss
Living the Longhorn Life: What's Up With Windows Server 2008 - Mark Minasi

Feel free to share with me your views and comments.