Besides the trading items that I have, I aslo bring what I call a Cache First Aid Kit. We all generally take care of each others caches, and sometimes I notice that people just post a note when they find a damaged cache.
I bring along an extra Tupperware container, batteries for camera flashes, zip-lock baggies, extra pencils and sharpeners, 2 log books, and paper towels for cleaning up dirty or wet caches.
Walt