I like the Garmin GPSMap series of handheld GPS devices. They are capable of road or off-road navigation. I use them for hiking and outdoor activities mostly, but they do a good job of road navigation (to lat/long as well as addresses). Note that you can get them cheaper at a sporting goods store!
https://buy.garmin.com/shop/shop.do?cID=145&pID=63800Check out the ETrex and Nuvi series while on the Garmin site. I have a friend that has a Nuvi. He can enter a lat/long, follow a road course, and then pull it out of the mount when he gets to the site and walk to the exact location of the coordinate. The 500 series does the multi-mode travel (on and off road):
https://buy.garmin.com/shop/shop.do?cID=134&fKeys=FILTER_SERIES_NUVI500
