win 2008 Ent server

That's quite a big question. Probably best answered by reading articles about it.

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Have also a look here:
http://www.microsoft.com/windowsserver2008/en/us/2008-ent.aspx

What’s New:

Remote Desktop Services: Enables customers to deploy a unified infrastructure for all their centralized desktop deployments, whether based on user session or on VDI architecture.

DirectAccess™: Allows remote workers to seamlessly connect to their work environment without the use of a virtual private network (VPN). (Requires Windows 7 Enterprise)

Live Migration: Enables customers to move virtual machines from one host to another with no perceivable downtime.

BranchCache™: Helps customers reduce Wide Area Network (WAN) bandwidth consumption between the datacenter and branch offices.

Windows PowerShell 2.0: Provides powerful scripting capabilities to help automate server deployment, configuration and management.

File Classification Infrastructure (FCI): Provides customers with a built-in solution for file classification and management.

Improved Power Management: Delivers new processor core and storage power management, reducing power consumption by up to 18%, and enhanced budgeting and metering capabilities.

Internet Information Services (IIS) 7.5: Delivers full support for .NET on Server Core, along with updated PHP support, new management tools, and bundled extensions.

Hyper-V® support for up to 64 logical processors: Enables customers to achieve higher consolidation ratios with new multi-core hardware and more scalable virtualization scenarios.

Source: MS marketing materials

Top Reasons to Upgrade:

Virtualization
- Reduce hardware and software costs.
- Optimize utilization and efficiency of the IT environment.
- Increase business capacity with lower total cost of ownership.

Enhanced IT and Power Management
- Reduce energy costs and carbon footprint.
- Simplify IT management and administration.
- Gain better control and manageability over the server infrastructure.

Advanced Web Technologies
- Simplify and centralize Web administration.
- Deploy a more secure and reliable Web infrastructure.
- Improve performance and scalability for Web applications.

Solid Foundation for Demanding Workloads
- Run demanding workloads with superior speed and efficiency.
- Easily scale IT capacity as business needs evolve.
- Enable employees to work more effectively in branch offices, on the road, or at home.

Source: MS marketing materials

Also have a look here:
Top Reasons to Upgrade to Windows Server 2008
http://www.microsoft.com/windowsserver2008/en/us/top-reasons.aspx

Hope i could help you shankarvetrivel :-)

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