The Garmin GPSmap 60Cx is an excellent gps. I've been using gps's of one sort or another for work (and play) for about 15 years now and the 60Cx is now our Departments standard. The newer model (as opposed to their first few runs) has a removable microSD card which allows users to load a ton of map layers (e.g. road, topographic, bathymetry, etc) or compatible GIS layers (e.g. pipeline, logging road, seismic cutline layers for access routes in the boreal forest) onto the unit. This model has excellent battery life, is waterproof, has WAAS and has incredible satellite receiving capabilities. The later feature is particularly important if you plan on using a gps in dense forest cover.
I occasionally use it for navigation while driving just because I own the gps, but handheld units like the 60Cx aren't the best units for this use as the relatively small screens don't cover much navigational area with the detail needed driving in unfamiliar urban environments. If I were going to buy a gps mostly for driving navigation, I'd look at the dedicated units with the larger displays.
The 60Cx is a fairly pricey gps as far as handheld mapping gps's go, but they are the best (accurate, durable, versatile and fast). I haven't used any of them, but some of the folks I work with have bought units from Garmin's cheaper eTrex line for personal use and have been quite happy with them.
