My Deuter Futura 28 is the best backpack I ever owned. I love the 2 compartments you can have in it : one is for my lunch the other one is for the random stuff I bring along. 28 Liters is just the right size for me. and you get the ventilated thing at the back that keep about an inch between your back and the bag. A little expensive ($100) but the last backpack I'll ever purchase.
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