John... A polygon mesh could simply a nurb surface where each vertex is a control point and every line is straight.
This is exactly my point - the only way you can achieve high detail with nurbs is to have the same number of control points as there would be vertexes in a polygon version of the same thing, in which case nurbs would be much much slower than simply using polygons (and with no increase in perceived detail).
The advantage to something like nurbs would be when you want to raytrace a perfect sphere, or other smooth mathematical shapes. If you had hardware nurbs raytracing support, this would provide excellent performance for simple blobby objects. But unfortunately for nurbs, the world isn't perfectly smooth and blobby, and the fact is that polygonal representations are much much more efficient than nurbs for anything but the smoothest of surfaces.