Hyper-V Replica. One of the best features of virtualization is easy disaster recovery, but this isn't as simple as it could be in Windows Server 2008 R2 Hyper-V. The clumsy process for setting up virtual machine replication in R2 gives way to a simple wizard in Windows Server 8. After you choose the virtual disks to replicate and the location for the replicas, you have the option of syncing immediately, scheduling the sync, or writing the replica to a local disk -- if you want to bring up the replica on a big USB drive and ship it to the other end for the initial load. The result is an asynchronous, application-consistent snapshot that's no more than five minutes behind the primary VM. You can even specify the IP settings for the failover environment within the replica, and failback is supported.
SMB for server apps. Windows Server 8 gives a big boost to small businesses and branch offices by extending support for Hyper-V virtual hard disks and SQL Server database files to SMB2 file shares. Translation: You can run your virtual machines and SQL database from a commodity file server, no special storage system required. To protect your Hyper-V and SQL workloads, you can create "continuously available" SMB file server clusters that provide transparent failover. That's high availability made very cheap and very easy.
VDI for the rest of us. Virtual Desktop Infrastructure will change the world -- but not until it becomes a whole lot simpler to do. Setting up and managing virtual desktops on Windows Server 2008 R2 pales miserably to Citrix XenApp/XenDesktop, for example, and implementing Citrix is no walk in the park. Windows Server 8 takes a big step forward toward reducing the complexity and costs of a VDI deployment.
RemoteFX no longer requires a hardware GPU, and remote connections appear to be much lighter-weight than in R2 (about 10% of R2 bandwidth in Microsoft's demo). Admins have per-user control over RDSH (aka Terminal Server) resource allocations. They have a single admin tool for full deployment, as well as a single unified way to deploy RDSH sessions, pooled (stateless) virtual desktops, and personalized (stateful) virtual desktops.
The virtual hard disks -- a new format called vhdx -- are specifically designed to store the changes and customizations users might want to make to the "gold image" that IT provides them. Although you can still store the virtual hard disk files on just about any SMB share, Microsoft is promising considerably better performance than the previous methods of storing roaming profiles that have given this technology a black eye. Bravo, and let the VDI wars begin ... again.