
MicroDEM is a very capable viewing and analyzing DEM tool. Most of the examples seen on the DEM main page were created with MicroDEM.
You can download a copy of MicroDEM here.
The SCO has created a guide for making your own 3-D views using MicroDEM. Visit our Quick Guide webpage for an introduction to this program.
The USGS also offers a free DEM viewer "Dem3d" that is very easy to use, you can find it on their DEM page.
Micropath is a retailer of USGS DEM data. They also sell a DEM viewer which allows for viewing many different formats of DEM's, as well as, converting between them. All the other standard viewing functions are included.