SolidWorks is by far the best 3D design package I've used, but, as someone mentioned, you would struggle to figure it out in your spare time. After several years of using it, its complexity is a boon, but it took me six months of daily usage before I stopped banging my head against it.
Basic AutoCAD is actually a fairly capable 3D application too. I used it in a commercial setting to draw 3D models of climbing walls since version 14. It doesn't (or didn't, I don't use it now) have any parametric modelling options, which makes revisions a bit of a pain. Creating plans in the layout side of it was always a bit time-consuming and repetitive too. It has a fairly simple scripting language with which you can make extremely sophisticated custom tools if you're into that sort of thing. The last version I've used was 2005, and watching the videos online I'd say it has progressed significantly in terms of ease of use since then.
I've tried to use Blender, but gave up in the end. The thinking behind how it works was too alien to me, which is a shame, as it's obviously a very powerful application with a vibrant open source community, and it's free. Really it's a 3D modelling and animation program though (3D modelling for games etc.), and I suspect the learning curve would be steep for most people.
Sketchup is another one that I simply can't use, despite how easy everyone says it is and me spending weeks trying to get to grips with it at work. It seems to me that it was designed originally for doing not-totally-precise architectural mockups, and has been hacked and coerced into other fields such as production drawings because it has a free version and is very approachable. So it always seemed to me that I was using some convoluted workaround to get it to do what I wanted. The lack of solids - everything is made up of surfaces - always seemed to make my approach not really work. That said, I've noticed that it's only people with a background in other applications (SolidWorks mainly) that share my view; most newcomers to it seem to pick up Sketchup easily.
Sketchup and Blender both have sophisticated scripting capabilities too of course, but I still think that AutoCAD is better suited to production drawings for woodwork.