I own the "large" size Mountain Duffle Bag.  It's super lightweight, and made from 900 denier poly nylon so seems like a good value for the price.  It comes inside of a small travel pouch that doubles as a mess or toiletry tote that would easily hold large shampoo bottles, etc.  The duffle has a large "U" shaped top opening for easy packing, two large zippered end panel pockets, front side pocket, rip-grip carry handle, adjustable shoulder strap and two end straps.  This duffel comes in small, medium, large and extra large, so be sure to pick the one that will work best for you.  My "large" duffle is 30 inches long, 15 inches high and 15 inches deep.  Comes with a lifetime warranty against defects.