Okay, here's how I like to use mine.
Buy a paper topo or Nat geo trails illustrated. The trails illustrated has grid lines based on Universal transerse Mercator or UTM. UTM is similar to what the military uses to call in an artillery barrage and used with the gps can be a very accurate positioning system.
So set the gps to UTM, and the datum to what the topo is drawn to, usually NAD27.
UTM is a metric grid, and based on 1000 meter by 1000 meter grid.
I take the coordinates in UTM and then place myself on map using the coordinates and the grid system.
Easy. Much, much easier than using lat/long. Using the UTM/MGRS map coordinate system
All I really want from my gps is the coordinates. Every thing else is just nice features.