There is also Artcam from Delcam, Express starts reasonably at 100 quid but a lot of features are extra

CNC Software For Woodworking, Jewellery, Sign Making, Routing, Milling, Carving and Engraving | ArtCAM 2011

Meshcam and Meshcam Art ,full functioning demos that can cut own parts

MeshCAM Art - Artistic CAD/CAM Software