I know many suburban homes have the garage attached to the home for convenience, but this can be a dangerous and smelly room and once attached, insulating and air sealing the habitable space of the house becomes more difficult to do correctly. On the aesthetic side of the argument, this room for cars is required to be so large, that it completely changes the massing of the house and often puts the primary focus of the building and site design on the car, instead of the people.
At the New House Next Door, the garage is designed for two cars - really it will house one car and a lawn tractor and stuff- and it is just a few steps from the back porch. It is built on what is called a floating slab, which means that the concrete footings do not reach down into the ground to the frost line, like the footings for the house do. The 6" thick reinforced slab has haunched or thickened edges that help anchor it down. The square building has walls with windows and doors and a gable roof built of wood trusses so that the 22' span doesn't require any interior columns. The exterior will have clapboard siding like the house, but the interior of the walls will have no finish, saving a bit of money and allowing my father-in-law to hang all sorts of tools and items easily inside. (Side Note: Attached garages need to be finished inside with fire-rated sheet-rock and a self-closing fire-door, to meet code, and cannot have open storage space above)
The builders have been building the garage as they've been building the New House Next Door. I will post photos of it from start to finish when it is all done, because I think it will be neat to see a small, simple building be built "right before your eyes" all in one post.