ArchiCAD

One of the most powerfull programs for architects with 3D/2D drafting and visualization. ArchiCAD allows the user to creating building forms, produce photorealistic visualisations and working with parametric objects.
New version of Graphisoft’s ArchiCAD brings some new capabilities, like energy analysis or Morph tool, which are helpful for users. In some part, like modeling enviroment, it gives you a lot of features, but it’s not simple in use, like first choice for that type of work – SketchUp.
This program can export and import DXF, DWG and IFC files. It’s available for Windows and Mac OS X and in number of license types.
With (also free) add-on’s or extensions you can get in ArchiCAD extra functionality.