For example, you can now attach simple JBOD (Just a Bunch of Disks) arrays via high-speed network interface cards that support RDMA. By leveraging RDMA, NICs can transfer data without bothering the OS, which means significant improvements in overall performance. This offload-to-NIC performance model is a common theme in Windows Server 2012, as you'll find other such features supported, including Receive Side Coalescing (RSC), Receive Side Scaling (RSS), Single Root IO Virtualization (SR-IOV), and TCP Chimney Offload. All this means that storage geeks will have an easier time building in-house storage arrays and even full-on SANS using just the tools provided in Windows Server rather than paying for third-party infrastructure.
With these new data protection, performance, and scalability features, Windows Server 2012 now has enough muscle that third-party storage hardware vendors may simply rely on the OS for storage management -- or it'll force those same vendors to raise the management bar. I expect these features will prompt many an admin, especially in midsized companies, to simply start building their own storage infrastructures with off-the-shelf parts, rather than spending a premium on more expensive turnkey storage.
Finally, with tempers running hot, I apparently must touch on The Great GUI Debate. Anticlimactically, this really isn't interesting to me. Yes, Metro survived the RC cut, which means it'll be in the final release. You can use the Tiles feature to pin oft-used management applications or even logical groups of network resources to the Start menu for quick access. I expect to see more Microsoft and third-party Windows Server Metro add-ins coming out over time.
But if you're one of the spear-waving anti-Metro tribesmen, relax. Remember that you can always turn Metro off. Indeed, Microsoft is pushing harder for a GUI-less install than a Metro-based screen. You'll find Server Core has been fleshed out with new depth and ease-of-use features, many related to the evolving PowerShell scripting language. PowerShell, by the way, is practically mandatory for Windows Server administrators going forward and well worth an in-depth look with another reported 2,000-plus commandlets added in this release --10 times the number released with Windows Server 2008.