Ah, the humble duffel. So overlooked, yet so valuable. Take away the duffel, and nobody would be climbing anything more than a foothill. When I climbed Denali? Duffel bags held nearly everything. When I interviewed Ed Viesturs for Sports Illustrated shortly before one of his Everest climbs? They photographed him atop mounds of duffels full of gear.
The Black Hole Duffel
As a slight digression, I will say that the most useful all-around duffelsparticularly for the priceare L.L. Bean's Adventure Duffel ($29-$59). Theyre tough, well-designed, and affordable. I must have a half-dozen.
But...they do lack shoulder straps. The North Face Base Camp Duffel ($135 in large) is just under 100 liters, has shoulders straps and side pockets, and is made from tough nylon fabric. Waterproof? No. But very water-resistant.
Black Diamond's Huey Duffel ($150 in large) does have nearly waterproof fabric, plus the other stuff you want. So that might be one way to go.
But I like Patagonia's Black Hole 110 Duffel ($175). Waterproof bottom, water-resistant uppers, the size you want, very well-designed with lots of tough handles and accessory pockets. Take a look at one.