I don't think a 3D printer in every household is going to make sense for a long while yet, if ever. Most things are well beyond 3D printing. You can't 3D print a transistor. You can't 3D print anything with even vaguely high tolerances. That said, a local 3D printing shop would be fantastic for the handful of times a year when it would be useful.
Perhaps more importantly, if you are the type to tinker, good 3D printing could be awesome now. Like cheap LEDs, only a subset of the population is going to go nuts with the technology, but for those folks, 3D printing is going to be awesome. It is all pretty niche, but those niches will love it. Indie board game designers are going to love it. Artist are going to love it. Folks who tinker or build stuff are going to get a kick out of it. I am sure that there are countless other folks who would kill to be able to make an arbitrary shape quickly and cheaply without having to have specialized skills or tools.
It isn't going to be an internet level revolution, but I bet some fields really notice. My personal pet field that is going to go nuts are boardgames. Being able to make cheap 3D printed objects to mass prototype is going to be killer in a field that is already experiencing a renaissance.