Many people like to transfer 2D CAD drawings to another program for colouring room zones or site plan. Usually they look to use Photoshop, but its very expensive.
There is little to choose between any of these bit-map and vector-drawing packages since all have far more features than could possibly be used. So choose whatever suits your style.
So why not start with a free one? A well regarded free vector-drawing tool is Inkscape.
Its popular with Mac graphics specialists, a good sign, and works with most flavours of Windows.
Its one of the increasing group of software tools developed, like WikiPedia by its users for their own use. As a result, nobody pays, and not just the people who developed it. As an open-source system, its well supported with clip-art and documentation, again free to use.
Well worth adding to your collection.
