If you want a big backpack, the Gregory UM-21 is probably the best made internal frame backpack on the planet today. It is huge, but it is made like a piece of hi-end gear should be. In other words, it is beefy and rugged. Everything about it shouts that it is truly a high quality backpack. But be forewarned. Ultralight it is not, but it was never intended for ultralight weekend camping. It was made for warfare. It was made based on the presupposition that the person carrying the UM-21 backpack would be out in the wild backcountry, possibly under hostile conditions, and would need to be packing a lot of equipment and supplies - but would still need to be mobile over long distances and for substantial periods of time. With that in mind, the UM-21 was obiously built not only for absolute reliability and toughness, it was also constructed with maximum load bearing comfort in mind. A person can easily carry greater than 100 lbs of ultra light weight equipment in this backpack. All the UM-21 needs is a hydration solution, for it has none. Add a MOLLE II 3 litre hydration pouch and a few small MOLLE II pouches (for quick-grab small items) and the UM-21 backpack (main pack, w/4 matching side pouches) shows itself to be the most magnificent bugout bag on Earth. If you like back country camping and backpacking, and also like to take lots of goodies, gadgets and gear along with you (and/or food, or whatever) - then the Gregory UM-21 backpack is the only real choice. It is reasonably indestructable, waterproof enough to withstand heavy rain for hours, big enough to carry most of your garage, and just plain super well built. And it is made in America. You just can't beat it. However, it should also be mentioned that the set-up for this beast is no small chore. The UM-21 has numerous straps and buckles. Numerous. And it can be configured in many different ways - so expect that you will be investing a couple of hours (at least) to fully attach everything and get it looking cool. The actual adjusting for fit/length also is somewhat involved, but a pdf manual can be gotten by searching Google for UM-21 backpack. The UM-21 backpack comes in desert camo and woodland camo. Too bad it isn't also available in black. The main UM-21 pack is part of a greater system which also includes a rucksack and a buttpack. The buttpack is a super nice addition to either the mainpack or to the rucksack. Certainly buy one if you can find one - just make sure that you pay close attention and do not purchase a 1/6 scale toy buttpack (for action dolls). UM-21 mainpacks seem to usually go for about $265, plus shipping (which will be a little expensive since the backpack is oversized for standard shipping, and when boxed weighs about 18 lbs). Make sure that the unit you intend to purchase has all four matching side pouches! Otherwise you will never find them, ever. The UM-21 mainpack is supposed to have 4 side pouches - one large, one small and two medium pouches that stitch into the MOLLE II webbing on the sides of the main pack. The total pack volume (and versatility) is greatly reduced without the four integrated pouches. I hope this helps.