The latest Casio Pathfinder is solar powered (which will last 5 months after being fully charged), includes an altimeter, barometer, thermometer, digital compass, and every other typical digital watch feature (alarms, timers, ect) only done better. For an MSRP of $450, this is a watch that any outdoorsman would lust after. Here is the point of this post though: Should a multifunction watch be included on the "outdoors essentials" list?
My logic in even wanting a watch such as the Pathfinder is the pure convenience of having so much useful information strapped to my wrist when in the backcountry. An altimeter (when correctly and frequently calibrated correctly) would give more accurate directions/locations when using a topo map, a barometer can be useful when trying to predict the weather (if you know how to use it), the digital compass would be convenient when wanting a quick reference for the direction you are traveling (although not the most accurate when compared to a mirrored compass like the one I use), and the solar power charge means that you are set when it comes to power (no having to worry about your battery losing its life in the middle of a trip [you should switch out your battery more frequently than required for this exact reason]).
In addition to the expensive features are the typical alarms and stopwatch - both would be very useful when on the trail. I still remember camping with a bunch of neighborhood friends a couple of years ago. They all had to leave right after breakfast the next morning, so I knew that I would need to get up at a decent hour in order to see them before they all took off. I woke up to the sun hitting the corner of my tent, and had an eery feeling that I was all alone although I went to bed with five tents surrounding me the night before. It was only 8 in the morning, but everyone was already gone! I felt like the crazy drunk uncle who everyone wants to avoid the morning after a night in the woods. I thought that I was getting up early enough, but only had the sun to wake me up. For this reason (and the fact that I typically want to get an early start on the trail when backpacking) an alarm on my watch would be perfect. No extra weight, very small, and conveniently located on your wrist whenever you need it.
The thermometer would also be very useful when backpacking/camping. I can't recall how many times I have woken up to a freezing face in the middle of the night, wondering if it was really below freezing, or if I was just a wimp. Having this feature on my watch would allow me to see how cold it really is at night so that I can see if my sleeping bag's temperature rating is more liberal than it should be (although I'll admit that there are small thermometers that are dirt cheap and very light/small which would be just as effective).
The downside? Price. How could a starving grad-student possibly afford a wrist watch that costs more than $300? Although there are other Pathfinder watches that are much cheaper to be found ($200 on REI), it's still an expensive watch. The solution? I was walking through REI when I saw a watch for $60. It was also a Casio brand, also had an altimeter/barometer/thermometer, and was pretty good looking. I don't know whether I will really use all the extra/expensive features on the Pathfinder, so why not buy a cheaper watch to see if the Pathfinder is really worth the money or not? Here is the watch that I found and later bought.
The bottom line: I wouldn't put multi-function watches on the "outdoors essentials" list. It is a fun and convenient extra gadget to wear around, but not necessary by any means. I will say, however, that any type of watch DOES belong on the list. Remember 127 Hours? Each and every one of those hours were counted by Aron Ralston while stuck in the slot canyon. Knowing what time it is may very well be the one thing that makes the difference between keeping one's sanity, and losing one's mind. Aron rationed out his water in order to make it last as long as possible. There was no way he could have kept track of time if he wouldn't have had a watch on him (high canyon walls and only a small window of direct sunlight would have made it impossible to tell the time). Some in hostage situations have also said that knowing what time it was made a huge difference (knowing the time of day gives one a small sense of being in control).
I know that I focused on the Pathfinder by Casio, but Suunto is also a very good watch, and may be more used by professional mountaineers than the Pathfinder is. As a side note, both the Suunto and the Pathfinder are BIG watches. If you prefer the more conservative, low-profile watch, these multi-watches may not be fore you.