For a long-distance bug-out bag?
A lot depends upon your environment.
Make sure you have two pairs of boots so you can rotate them, and the stuff to take care of your feet. Get a mesh mosquito suit. I think highly of the Tioga Kelty external frame pack, but other packs may work just as well.
A jungle hammock is lighter than a tent, but you need trees to string it from. A back-packing filter will provide water, a rudimentary first aid kit with vet antibiotics may help you stay healthy, Peterson's Field Guide to Edible Wild Plants should be included, a fire kit, a compass, maps, a hatchet, a ka-bar, a wire saw, lockpicks (and the skill to use them), freeze-dried concentrates, peanut butter, a canteen, a folding shovel, Castile soap, and so on.
Skill is more important than stuff.
Read Wild, by Cheryl Strayed. She hiked about 1,200 miles of the Pacific Crest Trail with no hiking experience, boots that didn't fit, she began her trip strung out on heroin, and was overloaded with a lot of stuff that she didn't need.
It seems to me that most people seem to think that they need more stuff than is actually neccesary (I'm not excluding myself here. My girlfriend looks at my stockpile and suggests that I'm starting to become a hoarder. She may be right.).
If you have food, clothing, shelter, water, weapons, and medical needs covered with the bare basics...what else do you need?