It's doubtful that you will see any next gen games revealed at GDC, unless they're for Wii U. We'll probably get some tech demos, however, some of which may be based on next gen games which will be revealed at a later date.
Really looking forward to the Next Xbox, especially how MS handles the UI experience.
I have high hopes for Kinect 2.0
I also wonder if Microsoft will release some games as "cross platform" titles with the next Xbox and the 360 for a few years (that is, to both systems; not cross platform play), similar to how they did with certain titles to PC and 360 (such as Fable 3)