Cotopaxi Allpa 35L Backpack
The main zipper on the Allpa travel pack ($130) allows it splay completely open, so you're never digging through the top to find something at the bottom.
Zippered mesh compartments keep everything organized inside, while high-denier polyester and nylon protect the outer from tears and rain. There are also sleeves for your laptop and tablet, plus theft-proof zippers and an included carabineer you can use to strap the bag to your chair at a coffee shop. At 35 liters, it’s a great size for a weekend escape and will fit in the carry-on compartment of even small regional jets.