Windows (server/client) 8
Both Windows Server 8 and Windows (client) 8 will be available in RTM versions before this year is done. I wish that Microsoft would just be up-front with us, and discard the Windows name, because it's becoming less and less relevant to the operating systems that are being sold to us.
Windows (client) 8 is centered on the Metro UI. In Metro, you don't have windows; instead, you have full-screen apps and tiles. If you insist on using the "legacy desktop," then, yes, you can still do windows, but all the real Windows 8 action is in Metro apps. So, I'll join the rabble who are suggesting that maybe this new version of Windows should be called "Tiles," because that seems to be the stand-out feature. Microsoft Tiles - just doesn't have the same ring to it...
Windows Server 8 is being readied to be a (largely) non-windowing product, with most of its emphasis on the command-line interface, focused on PowerShell. Again, Windows seems to be less and less relevant to the product as it's being presented to us potential customers. If we're going to be using a CLI, then why call it Windows anything? Just call it Microsoft Server. Then, on that foundation, you could buy Scenario Packs, to fit the basic Server core to different roles in the enterprise.
I don't think Metro is an atrocious user interface - on the right devices. I don't think moving away from a windowing UI is necessarily a bad thing for Server. But to continue to call these products Windows this or Windows that, is just becoming more and more misleading. If Microsoft is going to remodel the OSes to this extent, then perhaps it's time to consider renaming them as well. If you're going to start fresh, then why hobble yourself with old stuff, instead of new hotness?