This large haul bag from Metolius Climbing is one of the best. It is big, burly and relatively comfortable for carrying big loads. It is the perfectly sized bag for any serious big wall climber that plans to do a bunch of walls.
This bag is bomber, versatile, and pretty darn waterproof. If you are on an unlimited budget the main competition is the Yates Fat Sac it is more than twice the price. If you are on a tight budget, I would get the Fish Haul Bag. Otherwise, I am a bigger fan of the Metolius Half Dome Haul Bag because it is a more manageable size (you can easily get to the bottom of it). If you can only afford one haul bag, I would probably get the El Cap size because it will give you the most options. But I prefer the Half Dome overall.