Initially the idea is to make building blocks (such as Lego) from a 3D printer at home. There are a variety of designs out there and the geometries are simple enough that it wouldn't take long to create optimized patterns for each of the major printers.
Building blocks also have a fairly large following, and consumer recognition. The goal here is to have something that the average person or average family can relate to. In order to get 3D printers into more homes, we need something for average folks to click on and print.
Once I get the community underway I see no reason why the concept couldn't be expanded to other toys or even gaming miniatures. First we need a reason for Joe On The Street to buy a printer. Once he's got it and has discovered that he can print as many "Lego Like Blocks" as he wants, he'll be looking for other things to do with it. Warhammer minis, ships for Starfleet Battles (do people even play that anymore?! I do!), perhaps intricate puzzle pieces or completely unique toy items.
Each pattern needs to be optimized for specific printers. What runs on Makerbot needs to be translated to run on Solidoodle. Or RepRap. Or any other printer. You the average person should not have to deal with the CAD stage or ever have to deal with the raw code. You the average consumer... want to point, click, print.
Some of the more down-the-road ideas involve licensing various toy franchises. Perhaps your child collects Star Wars figures and toys. Wouldn't it be cool to go to Star Wars Figures Dot Com (a division of Disney toys and such international) and download the patterns for additional accessories? Background set-pieces, action-stands, additional gear and armor? Having grown up with an extensive collection of GI JOE I would have LOVED to have been able to do this.
Another idea down the road... Many people look at premium MMO items and go "eh I'm not paying to unlock ____ because it's just pixels on a screen." This comes up on Star Trek Online quite often... How would you like to pay to unlock that particular ship or weapon upgrade... and get the rights to print a model of said item for your desk? This could be expanded to ANY MMO cash-shop. Warcraft characters (with armor and gear), Secret World (character in costume), Champions Online (Action figure based on YOUR character) and so on.
These are down-the-road though. We need to give people a reason to own a 3D printer first. Start with something everyone enjoys... building blocks. Then expand outwards from there.
Does this answer the question or did I just confuse things more?