Here's a simple, yet pleasing example of Blender's Displacement Modifier done by Robert J. Tiess (RobertT).
For the texture I used the wood (ring noise) texture with low turbulence to establish the concentric sand lines.
After applying the modifier I used proportional editing to draw out some of the rings and alter height in different areas.
The ground mesh contains less than 80k verts.
The real-time displacement modifier is a lot of fun to work with and opens up many new possibilities.
Nicely done. You can view the original forum thread, here.