The main difference between 2003 and 2008 is Virtualization, management. 2008 has more inbuilt components and updated third party drivers Microsoft introduces new feature with 2k8 that is Hyper-V Windows Server 2008 introduces Hyper-V (V for Virtualization) but only on 64bit versions. More and more companies are seeing this as a way of reducing hardware costs by running several ‘virtual’ servers on one physical machine. If you like this exciting technology, make sure that you buy an edition of Windows Server 2008 that includes Hyper-V, then launch the Server Manger, add Roles.
Annembom Florantine Answered question