This will make the multi-monitor crowd go wild. According to Windows 8's group policies, the taskbar may finally be visible on all connected screens -- not just your primary screen! This has been the source of many complaints over the years and one of the most popular submissions to the (unfortunately now closed) Windows7Taskforce website. It's also the sole reason commercial tools like "UltraMon" or "Actual Multiple Monitors" are selling like hot cakes.
According to the settings description seen above, there might be a new "Multiple Display" section under the "Taskbar Properties" dialog. Unfortunately, this doesn't work in early builds of Windows 8, but it was even hinted at at the end of a 2008 PDC presentation on the Windows 7 taskbar: "Hopefully in Windows 8, we can actually get around doing a proper implementation of the multi-monitor taskbar."
It's yet unclear what the taskbar on the other display(s) will actually show: Will the taskbar on display 2 show only program icons visible on display 2? Will the clock and tray icons be cloned on both screens or only visible on one? Below is a mock-up of what a multi-monitor taskbar could look like:
