You may not agree with this, but give Autodesk's new Homestyler a try out.
I have tried out previous attempts by Autodesk to do this sort of thing, but this is way out in front as far as usability and so on.
It's primary function seems to be for interior layouts and it is is very good at these. Outdoor layouts are catered for as well, but it appears a pretty flat world out there.
I could see my friends computer-phobic wife getting onto this and producing a kitchen or two.
In the pic, I just slammed in some furniture and hit the render button, and it produced a fairly good render.
There are some things it does not seem to do:
1. Allow you to make your own content.
2. The window content is a little sparse as yet, but might grow.
What this shows is the shape of things to come: The tools of designers will become so effortless to use, that anyone can produce drawings. The new job of architect might then become what it should be: a dreamer, artist etc.
I'm still waiting for something similar to come along for mechanical drafting.....