I apologize if this is too high-level of a topic for PCB Layout forum, but it kind of fits here in many regards.
As for me…
Draftsight by Dassault Systems ( for 2D work, like PCB outlines, front panels, etc. )
- It’s free
- I learned years ago on AutoCAD, and Draftsight uses same commands, my finger muscles don’t have to be retrained.
OpenSCAD for 3D (for somewhat pretty 3D views of my board, depending on the fidelity of the part models, the results can be simply an illustration or a precise likeness - each has its uses)
- I started playing with it for reasons other than PCB, so I already knew it
- It’s parametric drawing capabilities are very useful to describe electronic parts, so many parts are the same basic part with different pin counts, for example.
- I found a github library where a fellow had already made a bunch of common electronic parts in OpenSCAD, and I just kept adding on to his beginning.
- It’s free.