Documentation and Communication:
As my first underwater camera retired after more than 3 years of service when its image sensor has conked out, goodbye D10 and hello to D20
This camera just like its predecessor is durable and keeps up to my lifestyle whether I go above the clouds or under the sea.
Why not an SLR? I consider it bulky, disturbing, and heavy while hiking. In short, it is not for this purpose.
An Android Phone that helps me record videos, geo-tag photos, take panoramic photos, guide me on sky charts, estimate measurements via Smart Tools, keep in touch via Instagram, Facebook, Twitter, Google+ in realtime... you name it. This is my modern "swiss knife". And it can survive some cruel amount of splash too.
Garmin Nuvi 1360
If I bring my vehicle with me, this is always on my dashboard to keep me on track and check on shortcuts create tracks for new roads as well.
Garmin GPSMap 62s
This thing is always tied in to my pack for two purposes: to keep me on the trail or to map "uncharted" territories.
Running on 2x AA batteries good for 24 hours and waterproof makes this thing reliable for extended hikes. Plus with an external helical antenna, it can get GPS signal even on dense forests.