From back in October, but nice to read a less breathless take on 3D printing in the MIT Technology Review:

As for everyone getting their own household replicator, Basiliere, Lipson, and other experts are skeptical. Even if printer prices fall drastically, making any finished product is going to require serious industrial machinery, with high-temperature lasers and powdered metals. Lipson envisions a 3-D printing ecosystem: some people might have printers at work—a car mechanic might have one for making certain parts, for instance, or a hospital for making implants—while other people might send designs to companies like Shapeways to be printed offsite. Some hobbyists might have small machines at home to tinker with, making bespoke Legos or other objects.

I've argued this for some time, somewhat unfashionably. Nevertheless, Josh Dzieza's closing paragraph is worth bearing in mind:

But Lipson also admits there could be surprises ahead. “It’s like having this conversation in the ’70s, trying to figure out how people are going to use computers,” he says. “It’s hard to imagine what business models will emerge.”