One thing that we have seen growing interest in recently is the concept of 'centralized desktops' with virtualization.  The idea here is that enterprises are able to create server farms that host virtual machines, which in turn run the desktop environment for their end users.  End users then connect to these virtual machines remotely over the network.

The main advantage of this model is the consolidation and centralization of the end user operating system installations, which can help with management.  However, there are a number of drawbacks with this approach today.

One of these draw backs has been that the Windows operating system licensing model did not provide for this sort of usage (prior to now - interested enterprises would have to purchase full retail Windows for each of the virtual machines).  But now, with Windows Vista Enterprise Centralized Desktop (VECD) Licensing - customers with Software Assurance agreements can license these virtual machines on a subscription based model.  For more details - check it this.