I spent $2K (X-carve). I've made spheres, cubes, boxes, various 3D shapes I bought on Ebay, and keep the parts around (they're nice to look at as well as hold during long meetings). A cube with filleted edges is particularly nice, although you can make that easily with just a table saw and a sander. If you sand it enough, it can be unbelievably smooth. or you can make it rough.
note that I'm mainly doing wood because the x-carve can't carve aluminum easily (no idea about tungsten). If I could make metal cubes, I would.
The actual hobby here is all sorts of wood projects, like tables, arts, etc, but I still make small geometry pieces all the time because I enjoy 3D graphical objects in the real world.
