Graphisoft ArchiCAD is a great software to realize 2D plans and 3D architectural projects, from houses to buildings with extreme design. Its easy user-interface, with the loads of design tools available allow to draw projects in a very short time.
Differently from AutoCAD, you do not have to draw each single part of your building completely manually: in fact, there is a tool for the Floor, another for the Walls, and a special one for the Roof. You can quickly choose and paste free and ready templates to drop Stairs, Windows, Doors, and even several internal objects, all fully customizable.
This software is recommended to amateurs and also professionals as AutoCAD, or both 2D and 3D projects. NB: to purchase this software you may need to contact a sales representative.