At the Sandusky Robot Games students entered a competition in which they must construct a robot capable of tossing a 40" inflatable ball over a set height. While they had many challenges in constructing such a device, they did make use of a 3D printer to manufacture certain necessary unique parts. The video shows the robot in action, successfully throwing the ball.
This event demonstrates a likely scenario of the near future: While we cannot print whole functioning objects, we can 3D print parts. And those parts can be combined with others that were made using other techniques to form complete objects. So, it seems that it's going to be a lot of "assembly" for now, and we'll have to leave the "Star Trek" for later.