Right now I'm considering the Ospery momentum The price is pretty expensive at ~$150, but I like the features and the fact it has a rain cover. I'm always paranoid about getting caught in a torrential downpour albeit rare and the contents getting soaked. Patagonia has a black-hole-pack that's water resistant but at around the same price. Does anyone know of less expensive options worth considering? There are other backpacks that have water proof material, but the zippers still leak.