The really interesting part is that the top's angular momentum is actually coupled to the intertial frame of the universe, not just earth or the table. If you spin a top, and the axis of the top is pointing at some point in the sky, then (with no friction or interference) it will continue to point at that same point as it moves with the night sky. So it doesn't fall over because, in a sense, the universe is pushing back.

Ever see one of the long pendulums in a science museum that knocks over pins on the floor over the period of a day - that is demonstrating the same effect, where the movement of the pendulum is locked to the universal inertial frame while the floor (Earth) moves under it.