I have a Garmin Etrex Legend. They can be had for ~$160 these days.
They're the cheapest Garmin with a built in base map, meaning you get roads down to about the state secondary road level, plus big rivers, lakes, etc... You can get cheaper GPS's, but most don't have any kind of map built in.
Mine has worked well in woods or in the car. Runs about 12-15 hours on 2 AA's.
The newest Garmins (Etrex Legend C comes to mind) run around $240. They have a built in basemap that has the capability to navigate using the map- meaning with the old one, if you said, I want to drive to Chicago, it would say "Chicago, 380 miles NW, 322 degrees". The newest one will guide you based on the roads, rather than just showing them. Has a better color display, and battery life over 20 hours.
I'm happy with their Regular Etrex Legend. A good all around GPS, IMO.