As someone who has spent a ridiculous amount of time under a pack, and owns way more packs than anyone ought to, I have very strong opinions on packs. Let me share some of my hard earned beliefs with you.
For starters, IMHO the holy trinity of packs is Kifaru (which are the toughest), Mystery Ranch (which are the most comfortable) and Eberlestock ( The most versatile and least talked about of the three). Arcteryx is their prophet on this earth (they make quality and comfortable gear especially in their LEAF line)
I have packs from all three of the trinity and have handled LEAF bags a few times, I wont recommend anything to you, that i myself would not purchase for myself.
The second thing I want to state upfront is that as with many things, you are going to get what you pay for. You need a quality bag, with a quality hip-belt if you are going to spend a large portion of time with a load of more than about 30 pounds on your back. You are correc tin your desire for a hip-belt, its going to save you alot of pain and possible injuries down the road.
Since this is your first "real" pack in awhile, I would recommend eberlestock since they are generally the cheapest of the trinity and their products are bomb-proof, I have a pack from them that I abused horribly and aside from discoloration is still ls good as new. I own 3 eberlestock packs, so again I'm not recommending you anything that I myself wouldn't buy.
Assuming that we have the same idea of what constitutes a 3 day pack, I recommend the X4, I have the X3 which is the same but with an added scabbard and it is a hell of a pack, like the Halftrack, which I also own, it has the ability to convert from one compartment to two, and it allows you to get at your load in two separate ways from both the top and the front. This is incredibly useful in alot of situations. Its got two hydration bladders for sustained time away form a water source. Like all eberlestock products it has an adjustable harness, your long torso will not be a problem. I find their hip-belts to be really comfortable, and their shooters harness is extra thin to facilitate good shouldering of a weapon. This best part of this is that unlike Kifaru and MR packs, they can be bought for less than MSRP, Unless you are Mil/LEO who get a 10% discount and awesome customer service, this can equal a substantial savings. The X4 can be had for under 160 bucks on a major retail site. Hint: Its named after a large river in South America
If the Eberlestock Line doesnt appeal to you, Mystery Ranch is another great company. I own their Sweet pea pack (the only non military style pack I own) and its incredibly nice. Its got bombproof construction, and a slew of really nice features. The two that appealed most to me are the tri-zip and the stow-able waist straps. The Tri-Zip is an amazing concept and i knew form the first time i saw one that I was going to have to purchase one. It really opens the pack up wide and lets you get what your looking for and lets you pack the heavy stuff in close to your back and upwards where they are stable, while still allowing you access to the other stuff. The Hip-belts are full featured and comfortable but still allow you to stow them in compartments on the side in case you need to climb with the pack on, or you k now that you are going to be taking it on and off alot. Also the sweet pea has this amazing beaver tail which lets me stuff dirty things on the outside of the pack instead of putting them inside, its got plastic stays that turn it into essentailly a giant bowl, capable of locking something as small as shoes or a balled up jacket to something as largew as an ACH in place without you having to worry about it going missing. They offer a bigger military style version of the Sweetpea called the Komodo, which as near as i can tell is identical to the packs alot of units use to carry COMM systems. This pack looks like it would suit all your needs and be really comfy, on the downside its pretty much double the price of the X4, additionally you may have no need of the BVS but youd be paying for it anyways (it works really well if you have never tried it)
Another option is the Kifaru ZXR, amazing packs. Aside form being stupidly tough, they can be overstuffed to a ludicrous degree. I havent owned one, but the Zulu which is the smaller version of the zxr would be a really good fit for a three day pack, But since my familiarity is with the ZXR and Armor Grip 1 i cant really tell you exactly if it would suit your needs, other than to say Kifaru makes amazing products.
The only other thing I would consider wpuld be an old school, metal framed alice pack. The guy who started tactical tailor got his start enhancing them, and they still do the best ruck mods on the market.
Hope this helps, Good luck on finding the pack thats right for you.
