MS Student
Simple programs to animate examples and spit out well rehearsed explanations will be trivial.
More advanced programs that can dynamically assess which parts of a problem are not well understood will help.
Situationally aware programs which have an excellent idea of what the student is reading and maybe thinking, in addition to long term performance tracking, will be amazing. At the very least, a program that can discipline a student for not paying attention will be a roll reversal.
Also, more specific domain knowledge will allow an education frame work to be easily applied to a new area. I am very hopeful about the potential benefits. Bringing world-class education to anyone who has access to a computer (which, considering public libraries, is everyone in America) will be revolutionary.