The short answer is "the one you use". Chris suggested some great resources. Look up contact information for a local orienteering group to get more experience. It's a lot of fun and can be good exercise too!

I use a Silva Ranger compass almost every day in my profession (no, I don't get lost all the time <img src="images/graemlins/smile.gif" alt="" />). Suunto make one almost identical. The important feature for me is the ability to set the declination. This is important when locating land boundaries or performing simple mapping measurements. It also has a built in clinometer (or "inclinometer") which can be used to measure slope gradient.

I like the "sighting" type compasses the best. They have a mirror on a hinged lid which enables you to sight through a notch over the compass while looking into the mirror and aligning the north arrow. I've always thought the mirror would make a good signalling device as well. I know it helps when you get something in your eye. If I recall correctly, Silva makes one called the Guide which runs about $15. While you cannot set the declination it does have a declination scale which allows you to easily account for it.

Remember to bring a map with you too. If you're lost you can usually figure out a bearing to follow to get you to a road or stream. Trust your compass. Lots of stories are out there about people who had a compass but didn't trust what it told them. That needle is going to point to magnetic north unless you're standing on one of the poles. I'm not so sure about a GPS unit, however (and I teach folks how to use them as part of my job!). Electronics and batteries fail, coordinate systems can be tricky, and most of us refuse to read instructions anyway. Even if you carry a GPS unit I encourage you to carry a map and compass (and know how to use them). I'm a map nerd anyway. When the weather's bad outside I curl up with a good map and dream of where I want to go next.

Terry

Doug Peacock, inspiration for Edward Abbey's George W. Hayduke carried a map of his old backpacking haunts in Vietnam and did the same imagineering. As a Coast Guard Quartermaster, I was known to slip in bogus charts with stylized Tolkien seadragons and warnings of "Mer Incognito." First time compass and chart users should get their local area. You can easily translate local landmarks with the maps- assuming they haven't been 'developed.' <img src="images/graemlins/frown.gif" alt="" />

Maps and compass go together like ham and eggs. Actually, if I had to choose between the two, I would rather have a map, at least for the country in which I do most of my rambling, the SW United States. In most areas here, it is very easy to orient yourself by visual references without recourse to a compass. In general, a USGS topo map, 7.5 minute series is the best for foot travel. But about every five years or so, descending fog or something restricts visibility and renders a compass an absolute necessity.

There are many ways in which a compass needle can be influenced to give an erroneous reading - locally carried ferrous objects (like the screws in your eyeglasses!) or local bodies of ore. Specifically, if you are climbing Orizaba, your compass will be out about 70 degrees. I had a long discussioon with my climbing partner who was using his compass, that was only settled when I pointed out the location of the North Star. But yes, basically the compass needle is usually right, and definitely right far more often than ones instincts.

I currently carry a Suunto MC-2 which has an inclinometer and mirror. The mirror definitely works well for signalling and even for shaving. Accurate, compact, and light.