As a self-professed "Bag & Pouch Addict" I have tried over the years to find the perfect bags and pouches. For the most part I have been disappointed in most of the packs and pouches I have owned, and of late, I've been getting rid of bags and pouches that I simply don't use. I've found that what's left all seems to share these basic design principles:

Simple Construction - minimal, if any, interior specialty structures, key fobs, pen pockets, ipod sockets or other apparently task-specific construction elements. Some days I need to carry more than 2 pens. Other days I need to carry more than one laptop. Simple construction lets me organize the interior as I see fit.

All Chambers Close with Zippers - Not velcro, latches, snaps, buckles, buttons, turnbuckles or lashing - just good, high-quality, sand-proof, user-proof Zippers.

No Open-Top Chambers. Inversion, dropping and throwing a bag should not cause any contents to come out.

Very Strong Materials & Durable Bottoms - My bags get dragged, thrown, dropped and rolled on cement, dirt, rocks gravel and snow. I don't like it when a simple drag over 12" of cement leads to a ruined bag.

At least water-resistant, if not water proof. - This is a tough standard, but for me, it's grown into a must-have, I'd even settle for a single dry-section of a "normal" bag, but I don't want to have to find out that the bag I tossed up under the bow of the boat 3 hours ago during a body recovery search on the lake ago rolled back and landed in the bilge and now my maps, camera and batteries are soaked. A fully waterproof bag is a bit heavy and expensive if you have waterproof zippers, but a dry section would be great.

Porta-Brace brand products are the closest I've found to meeting these requirements, Pelican also makes some really good bags these days.