Google Sketchup is a Great Free CAD Program
by Greg
(SF, CA, U.S.A.)
We use Google Sketchup in our office for simple 3D models and it works great!
We've used it mostly on 3D houses but have also done some larger commercial buildings to show the scope of work to the customer.
Easy to use and free, Google Sketchup does all we need to do in 3D. I'm sure we'll eventually end up upgrading to the pro version for $500, which is still a good price considering the prices of 3D software programs on the market!
By the way.. great job on compiling the list of free CAD software on your site. It's nice to have one place to go to get what you need.