I'm growing very fond of handheld GPS products from Delorme, a company from Maine. They now let you load NOAA maps, satellite, USGS, street, topo, and aerial photography. The accompanying software is pretty sweet too. You can customize the maps and routes. Print your own maps. You get unlimited map imagery downloads for $30/yr extra.
One version of their handheld gps has a SPOT satellite communicator for emergency messages.
They're well worth checking out.
http://shop.delorme.com/OA_HTML/DELi...?section=10460
(I don't work for them but have been using their software for many years.)