I've used 2D CAD packages for years. TurboCad has been my weapon of choice, but it's not in the same league as some of the biggies - SolidWorks, AutoCAD, Pro-Engineer (the last of which, according to my wife who has a degree in Industrial Design, I was lucky to avoid).
Anyway, recent events have prompted me to start playing with Sketchup, a free tool provided by those wonderful people at Google. Here is my first attempt - I leave to you the decision of whether it's worthy of the fridge door (please be nice!)
The models of the Molex connectors were downloaded as part of a brand new initiative that is very exciting - do take a look...

电子发烧友
Hello! I would like to ask Google Sketchup
How to export the STEP 3D format
Thanks
LStacey
Your design looks pretty good to me!
I love Google Sketchup. It is completely free too! They do also offer a full price version with more features and corporate licensing options if you want to delve in a bit deeper.
More info:
http://sketchup.google.com/index.html