To further expand on Hecklers post, MasterCam is good, Teksoft integrates well with SW via CAM Works, and Surfcam rocks for moldmaking. I would avoid programs like Gibbs, Esprit and other inexpensive CAM programs, you get what you pay for. If you are primarily doing simple milling and turning I would go with Camworks, if you are talking about EDM, Lasers, 3+ axis milling than I would go with MasterCam or Surfcam.