This is my new bag. It weights 1 pound, 13 ounces and has a two liter hydration bladder. I got it at Walmart for $20. I haven't decided if I like he bladder yet. Whenever I put the bag down, I'm afraid of the sip tube rolling around in the dirt.
Here it is with a bunch of stuff. I was a little bit surprised how much stuff straps on the outside. There's my pad and flip-flops and headlight and sleeping bag in a poly sleeve; hammock. Right now the only stuff inside is first aid, iodine+dropper, bug repellent, space blanket, tent pegs, 20ft 550 cord, umbrella, knife, compass, bic lighters, whistle, spare LED clip-on light, little shovel, wipes, hand sanitizer, couple of bandannas.
Oh, and an inflatable pillow. I made a muslin pillowcase which could be a cloth bag in an emergency that requires a cloth bag.
I'm pretty sure that's a little more than I'm likely to need, if I'm out between dinner and breakfast. I think, with the addition of some food, clothes and a few more toiletries, that it'd work for more than a day. I'll try it out and see.