3d sculpting and painting
Sculptris provides an excellent gateway into the exciting world of 3D. It's features are easy to learn, even for someone with no experience in digital art, yet robust enough for creating base models that can then be refined in other applications.
Maker's Empire is tablet software (iOS, Android, Windows) for easy creation and 3d printing. It is easy to use and aimed at children and undemanding designers.
Expensive high-end 3d modelling. Create, edit, or repair geometry without worrying about underlying technology.
Nvil is completely focused on modelling, which allows it to maintain a very clean UI and slimmed down tool-set, focused on just subdivision and polygon modelling. Extensive customization functions.