I might need to clarify, by worthless I meant it has little to no resale value, where as machinery always has a cash value, even for scrap metal if it gets to that point. I won't argue that good software can make you money, and lots of it, but that's all dependant on your staff and sales. If you feel you have an established client base them you'll have a better idea of how much you can invest.
I missed the end where you mentioned Cnc capabilities being important. If you're at that stage then I don't think autocad is a very smart investment for you. If you're planning on having your Cnc work outsourced then I would suggest using whatever they use, or even just letting them draw it in their own program for production.
If it's being done in house then I would stick with cabinet vision for kitchens and somewhat basic cabinetry, it does a fantastic job of uncomplicating the small details once it's set up. But if you're doing more complicated commercial type work then micro vellum would probably be your best choice. I don't think there's anything it can't do.
There's a lot more options in between, but those tend to be more of a bandaid, micro vellum and cabinet vision will definitely grow with you, and if you're getting anywhere near what you should be getting out of them cost won't be an issue.