[emodendroket]

Well, as they currently exist, they can only create things entirely made from plastic, so I don't think they'd be too helpful.

[detaro]

The printers people can afford for at home, yes. 3D printing companies like Shapeways will do your designs in many other materials as well, including steel.

[joshuapants]

I'm hoping that someday we'll be able to print integrated circuits and other components right onto a board. You may be able to print out a new joint for your robo-dog's leg, but if some capacitors blow and it's all SMD repair is a lot harder at present.