I like RhinoCad, you can download the demo and the only cripple is you can't copy or paste drawings or pictures and you can only save 25 times. After your 25th save, it just won't let you save anymore, it doesn't lock you out. Thier tutorials are great and there are MANY plug-ins depending upon the type of work you do. I use RhinoCam for my CAM system, there is also MadCam, and atleast one for shoe sole manufactures and quite a few for jewelry makers.
Don't get sucked in BobCad, the only reason you see so many posts about BobCad is because they suck in so many newbies and thier software sucks. Rhino is comparable to Solidworks, starts at $900 and add your plug ins from there, vs one of the full feature programs such as Solidworks, MasterCam, ect costing $5k and up.