@Clint: Yes. All 3D printers require 3D solid models as input. If you create your own models, you can print them. The trick is to make sure the models are "solid", aka "water tight". Most 3D graphics tools are tuned for video production, which does not require true "water tight" solid models. You can get away with meshes that have no thickness (think: clothes, hair) when you're creating a model for video, but thickness is required for 3D printing. AutoCAD, Rhino3D, 123D, and MOI are modeling apps you can use to create 3D solid models for printing.
There are many different styles of 3D printing hardware, too. Each has its own strengths and challenges. I use a ZCorp Z406 powder printer to print in plaster and clay: http://dannythorpe.com/category/ceramics/
As for your comment about "not totally here yet": true, if you're expecting something that is as hands off as a modern laser printer. 3D printing still requires a lot of "user participation". There are a few 3D printing systems that are truly hands-off appliances, but you pay a premium for it: such machines from ZCorp / 3DS and others cost $20k and up. You can expect 3D printers from the maker space to require a bit more hands-on engagement. First you have to build it, then you have to feed it, understand its quirks and limitations, etc.