Another way to make simple stones meshes that are similar to Bryce stones and can be a little more varied in shape is to use the Organic construction method in the Vertex Modeller:  

Insert Vertex Object, using polyline tool draw an irregularly shaped polygon with 5 or 6 vertices, then fill the polygon ("cmnd/crtl F" or menu Model>Fill Polygon).  Then hit menu Construct>Organic and you'll get a low poly mesh stone.  From the Properties tray, apply Subdivision Smoothing to taste.  

50parsecs' sphere-based stones are probably better for many purposes (easier, lighter on resources), but Organic stones can be handy when you want stones with more "lumpy" shapes.  The stone in the pic came from a 6 point polyline, and ended up with 30 polygons and 45 vertices.  

*Quote - ... But the default ground plane mat is very horrendous! So I really wish they would in the next edition of Bryce change the mat to one that loads real fast like the basic gray. *

Here is what I do:  change the default ground plane to basic grey.  Set 'Document Setup' to your usually preferred size (if it is different from the default).  You can at this point change anything else you want, such a new sky - but I don't bother.  Finally, 'SAVE AS'.. this scene into the same location as the Bryce application file, naming it 'default'.   This is now your new default startup scene, complete with basic grey ground plane.

I used to do this in Windows, but now I'm on Mac and it works there too.  So far Bryce 6.3 seems to be working well with my iMac and MacOS 10.6.2.  

drawbridgep - 3 pts - first in, best dressed! Prufrock81 - 2 pts - most amusing Walexander 1 pt - great design and concept ... enjoyed them all - this was fun!