As a mechanical engineer and application manager I thought it would be helpfull to join the discussion.
For 2D: AutoCAD is simply the best known application. It has it's limitations but it's just the best-known and most used CAD application around
For 3D: SolidWorks is probably the market's standard.
Forget about Catia and Pro-Engineer. That's for whizzkids and weirdo's with too much time.
The company I work for uses 7 CoCreate OneSpace Designer (3D) licenses including their Model Manager and 2D Drafting (previously ME10). Designer has a very different method to build up 3D models which I think is very easy to learn. It has a no part-history, no constraints, no bull-shit user interface. It's basically what you see is what you get. AND THAT'S GREAT! I love the program although it has it's limitations. You only come to the point of limitations when you want to program something that builts up machines/ parts automatically, but that's probably not what most people here are trying to do.
There's one problem with OneSpace Designer: It has a very limited user group so you will probably end up asking me questions?
CoCreate now offers a Personal Edition. This is a limited edition of the program I use at work. It's able to handle up to 60 unique 3D models and needs an internet connection to start up.
I really hope this was helpfull to anybody. Please feel free to give CoCreate OneSpace a try (sorry, you need to register first). I think it's worth it.
https://apps.cocreate.com/OneSpaceMo...E/register.cfm
Gr,
Michael