> I'm thinking about thinking about getting into > geocaching. What would be a good GPS device? I > don't want to get a "beginners" unit then move > up after I get experience. I want to start off > with one I can use for a long time.
The list might be able to better assist you if you told us a little more about your situation, such as:
how much you're willing to spend initially;
how much you're willing to spend over time for map data updates;
how comfortable you are with technology (i.e., is initial ease of use important to you or are you willing to invest some time in reading the manual);
whether you have any affinity for a particular brand (i.e., Garmin, Magellan, etc.),
whether you need a color display;
whether you want an internal compass and barometric altimeter;
whether you prefer a unit that has a rechargeable battery;
whether you might want to use the GPS receiver for in-vehicle navigation; and the like.
It doesn't make much sense to recommend a $350 Garmin GPSMap 60CSX if your upper limit is $200.
If you're really insistant on expecting your first GPS receiver to satisfy you for a long time, you should do a lot of your own research to supplement any recommendations you get here.
> Also, could a GPS device used for geocaching > also be used for hiking (like in the woods).
Most GPS receivers sold in the consumer market, excluding those designed for in-vehicle navigation, and excluding multipurpose devices (e.g., cell phones, PDAs, etc.), would be suitable for hiking. The features that make a GPS receiver good for hiking include (1) presence of recreational navigation features, including appropriate displays, a large number of waypoints, deep track memories, track-back features, etc.; (2) light weight; (3) good battery life; (4) water resistance; and (5) a highly effective receiver and antenna.
Receiver performance varies among brand and model and can be important when hiking (and geocaching) because tree cover attenuates GPS signals. As an example, here's a web page that reports a comparison of two high-end consumer GPS receivers, in which one receiver appeared to perform significantly better than another in terms of the number of satellites the receiver was able to use to calculate a fix. This might (or might not) translate to better performance in the field.