I have had a Magellan Meridan Gold for about a year now, with their topo mapping program loaded into it. In addition to the built in memory, you can use a SD card, with a ton of info on it. When out on foot I can have it show topo lines, mines, wells, you name it, anything that is normally on a USGS topo map. I have a mount with power cord in both of our vehicles, when on the road I can have it delete the topo lines, but show gas stations, campgrounds, national and state parks, harbors, you name it. You can program it to show lat long, or UTM. The screen is large enough for me to see while driving, and the unit, while larger than some other brand GPS's, easily fits into a field jacket pocket, or I have a belt pouch I can carry it it. It is the only GPS I have ever owned, and I am more than happy with it. Be sure to check prices on ebay, I got mine there for about half of the MSRP. Same for the mapping software...