Russell, regarding routing PCBs and CAD, I think you will probably need to do some processing on the output file from just about any CAD package. There's a company producing dedicated PCB routing tools (LPKF at http://www.kpkf.com) and we bought one of those machines at work. Very good is was too. I remember that the PCB file in gerber format had first to be translated by the software provided with the machine. This worked out tool paths to remove copper in the most efficient way, using large tools for big areas and small tools for fine pitch parts. It calculated how far it needed to be from the track according to tool width etc. Perhaps your setup does the same. The motor in that machine span at some ridiculous speed – I think it was something like 26,000 rpm which was necessary to get a decent cut. And the cutters wore out quite quickly, due more to the glass in the laminate than to the copper.
As for the comments on free software made by several, I quite agree. I was one of the first to sign up for Alibre. When they launched, it was called something else (X-CAD, I think) and if you we're one of the first 10,000 to register, you got some enhancements in the free package. It came with a promise of 'for life', if I remember correctly. Then they cut it down to almost useless unless you pay for the hobby version. I don't use it anymore.
The 3D software offered by RS Components looks very capable and comprehensive. I've only tried it for a few hours but so far I'd say it's as featured as Alibre. It could well be based on Sketchup but is definitely an engineering package. One of the reasons I'm prepared to invest time in it, is because RS are behind it. Their goal is to provide software free and I don't imagine they would suddenly change that policy, in the same way that Alibre did.
The commercial version at http://www.spaceclaim.com is probably a bit more capable than the free one but if it is like the PCB package, new features should be added fairly regularly.