The Surface Family
Ballmer called them the Surface family of products and so far we've seen the Surface RT and Surface Pro along with Touch/Type covers. So the question is if the Surface devices do well, will we see more and if so what comes next. So this is is what I think is coming next for the Surface brand.
Keyboard dock and a traditional dock for charging and more ports
Surface Xbox: a 7 or 8 inch tablet to compete with the Nexus 7 and iPad Mini (could be switched with whatever Barnes and Noble does). Surface Xbox will be aimed at mobile gaming, reading, consumption
A Surface Ultrabook: 11 and 15 inch models which take the Surface Pros design and rework it for a laptop
Last Surface All in One: 27 inch all in one with adjustable screen
So that's what I think COULD happen with the Surface brand; a set of products built to highlight targeted form factors.