In April, 2005, I bought a Garmin ETrex Legend color GPS to use while hiking. I owned two other Garmin units at the time, was very pleased with their performance and service, and decided to stay with that brand. I am sure there are many other fine units out there from other manufacturers. I also bought the MapSource topographical software for the West National Parks in 1:24,000 scale.
The ETrex Legend is identical to the ETrex Vista except it does not have a barometric altimeter or electronic compass. Those two features would add about $50 to the price, something I did not think was necessary. GPS already shows your altitude and with any movement, you instantly know what direction you are heading.
I really like the color display over the black and white display of my other two units. This unit is extremely compact, light, and operates up to thirty-six hours on two AA batteries.
This model has 24K of memory for software downloads. A new model that is just out, the ETrex Legend CX, has memory cards that allow virtually unlimited software downloads. You first install the MapSource topographical software on your home computer. You then download whatever regions you want to your GPS. I have most of the Grand Canyon downloaded to my GPS and still have not run out of memory. I really enjoy using the topo software on my home PC too. That lets me preview any upcoming trips and get a good feeling for what I will be seeing on my GPS. The topo software displays almost every trail in the Canyon, elevation contours, creeks, streams, canyons, buttes, etc. It's difficult to be lost with one of these units with you. I won't be making any hikes without my GPS in my pocket.
In November, 2006, I bought a Garmin 76 Cx. This unit has a larger color display than my Etrex Legend, but is also physically bigger. I clip this unit to one of my pack straps as it is too large to fit in my pocket. This GPS uses memory chips where the Legend had a fixed amount of memory. I bought a one Giga-Byte memory chip for this GPS, which allows me to download just about any amount of my topographical software I want. I also have the ability to enter waypoint coordinates directly from the unit instead of having to download those from my home PC.