For some things, absolute minimalism is best. Bags for organizing things inside your pack definitely fall into this category. You don't want to pull out a dozen individual dehydrated meals one by one, but you also don't want to use a pound of sacks to contain them.
Granite Gear hears you, my friends, and gives you the Air Space ultralight zippered storage bags. Available in four sizes, the medium weighs in at 1.7oz (size medium) of 30D Sil-Nylon Cordura with a waterproof YKK zipper, complete with pull cord. The material is translucent so you can get a good idea of what's where on the inside before you open it. It's got a grab handle at each end, but be gentle: I ripped one off after overloading it and giving it a good yank.
These things are absolutely perfect for stuff like clothes and food. You can easily cram a dozen dehydrated meals plus smaller food items in a size medium, and it fits nicely flat inside most expedition packs. I used two for food and one for clothing last season on Denali and just loved it.