Just curious about this. I was packing for my trip along the GAP and C&O on Thursday and had whittled down my gear from my last tour. I dropped a lot of clothes, but the one thing I can't give up is my netbook. Yeah it weights 5 pounds and takes up space but since I suffer from insomnia it helps to keep my from going crazy if I wake up in the middle of the woods at 2am and can't get back to sleep.
Just curious what other people bring along that they know is completely unnecessary but they wouldn't travel without.