SolidWorks - Dassault Systèmes SolidWorks Corp. develops and markets 3D CAD design software, analysis software, and product data management software. SolidWorks is the leading supplier of 3D CAD product design engineering software.
Mach3 - Mach3 is very popular among the Hobby CNC community.
FreeCAD - An open-source parametric 3D modeler
LinuxCNC (the Enhanced Machine Control) - LinuxCNC: an open source CNC machine controller. It can drive milling machines, lathes, 3d printers, laser cutters, plasma cutters, robot arms, hexapods, and more.
SketchUp - 3D for Everyone
Mastercam - Mastercam's Dynamic Milling is a game changer for us.