Solving the Knapsack Problem can be a very hard task, especially when you know, that you will wear the knapsack on your back for about 2500km in the next 8 days!
I have decided to rate the water bottles, the first aid kit, and the fresh underwear at highest value followed by gloves, Nikon N1 camera (thanks to Anna to remind me on that!), and Nokia Phone (thanks to Michael for borrowing!) with German SIM card (thanks to Beat for providing!).
Good luck!