Not sure how many of you use a laptop while exploring or even tote one in the vehicle for navigation... But, I have been using a program called USA Photomaps for prob 5 years now. It was made by a retired airline pilot for fun. It allows you to enter in an address, GPS coord and other such things then download B & W satellite photos of the area and (to me) the best part, the USGS topo maps for the area. I have all of Wharton downloaded. I also have my geocaches downloaded to it. It will also integrate with a handheld GPS to show a real time location on the map or if you are a ham (I am) APRS data. All data is downloaded for free from the teraserver web site, his program is just a simple means to assemble all the date. His program is free and can be found on JDMCox.com
screen shot: http://jdmcox.com/Sample.jpg
screen shot: http://jdmcox.com/Sample.jpg