This question gets asked periodically, but it is fun to revive it and let the current crop of posters loose on it.

I rarely go backpacking without a paperback book. Even my camera gets left at home sometimes, but never a book. But, of course, my second most taken luxury is the camera.

Combined, these two luxuries of mine account for about 1 pound, depending on the exact book I take. They aren't really necessary, but they do make the trip more fun.