Before you buy Alibre take a look at SpaceClaim. SpaceClaim and Rhino work very well together. You can start a model in either software, use the supplied plug-in to fire it into the other software, do whatever you need to, then send it back.
As for CAM, we use WorkNC and madCAM. I used to consider WorkNC a high priced software until we bought Esprit for our mill/turn. Now I would say it's priced in the middle of the spectrum. madCAM works right inside Rhino and is a very capable software, and very inexpensive. It does everything from 2 to 5-axis. It's worth a look for sure.
Hope this helps.
Dan
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)