Getting excited about my Shapeoko3 shipping...and now wondering what software to start getting familiar

Getting excited about my Shapeoko3 shipping…and now wondering what software to start getting familiar with to design and generate GCode. Any suggestions?
I’ve used Corel/Inkscape/Sketchup before with my laser and 3D Printers

Freecad to cambam to chilipeppr

@Andrew_Spurgeon I also agree with @Mark_Bystry that Autodesk Fusion 360 is excellent. It is FREE to enthusiasts and home users NOT in a business making over 100K. It will generate .stl files and has Fusion CAM as part of it. Down side is the learning curve which while not steep does take a bit of concentration from the beginning.