Do It Yourself Deck Design Software
Deck Designer - Windows XP
DIY design and estimating software to create stylish, multi-level decks.
* Not recommended for Windows Vista
Basically a very intuitive piece of software and makes creating deck designs a pleasure. This program also has an export .dxf file function so it can go into a CAD system to build in conjunction with a bigger home design you might have in mind.
In this price range it is also good value. When you are talking about $50 or less for deck design software all of these entry level programs offer, it's hard to say no.