Have used most mentioned here, I also bought Maptech 3D Terrain Navigator and a couple of state databases. I especially like the profile views and info when hiking mountains. There are some free marine maps from their website, showing buoy markers, numbers, etc. Also check out their marine contour product, pretty amazing, then again, you might -not- want to have a running underwater 3d view of whats under your ocean kayak!

Bill/Dave, can you give a bit more info on those hard to find DEM maps? That might help me, I have lots of hard drive room :-))

: I researched this before and it took a long time but I found the files needed
: to create a 3D map in the kirkland washington area. If I remember right
: the DEM files were the hard ones to find. The resulting 3D file was huge,
: somewhere around 78MB. It was fun to do but sure ate up my hard drive in a
: hurry. Once I upgrade my computer I'm going to create some more of these.