If you want to create 3D models for inventing, mechanical engineering, or high-accuracy simulations, you can try to learn Solidworks, Autocad, Inventor,Creo,UG or Catia.
If you want to make models for video games, movies, and special effects, you can choose Maya, 3DS Max, Cinema 4D, Modo, Lightwave, DAZ 3D, Rhino,Carrara or Blender.These are complete packages that can do many things.