I've had good luck with my Garmin -- I think it's the 60Csx.
You can upload local topo maps for the region you're trekking. It has a bunch of features that I rarely use, but it's very accurate and has been helpful in blood trailing deer at night (when you lose the trail, you can look where you've been and note what general direction they were last moving in -- has been a great asset several times in recovering deer), and I've used it extensively to mark fishing spots in my canoe.
It's simple to use, doesn't eat a lot of batteries and is great for exploring deeper in the woods than you might normally be comfortable with.
One thing it DOES require is that you calibrate the compass each time you turn it on. This consists of spinning slowly in a circle (the GPS tells you what to do). It's an absolute necessity for using it in the woods/trails, as its directions are only as good as the compass's calibration.
It's very sensitive, and is good for things like recording the length of your bike rides, doing a little Geocaching, and other things like that too. I use mine all the time.