The ATS RAID II.
A few different configs..
It's a bomb-proof, well built pack. It can hold a lot of crap, and can be cinched pretty small. I use a USGI waterproof bag inside, and small items in the MC pouch mounted to the flap.
The pack is used for everything - carrying the laptop to work, assault pack for field operations, training, shooting rest, running, light hiking, light camping...
I find it much more comfortable over armor than most packs. I used to own a TT enhanced 3 day pack, and while it would look comfortable - it really wasn't over armor. I don't use that one anymore because the shoulder strap got shot and I lent it to a buddy.
I would recommend the RAID II to any infantry or SOF dude who wants a nice assault pack. It isn't as useful for a civilian.
My advise? Get the frame insert, mount a couple of pouches to the inside for organization, tape up your straps (obvious) and it will serve you well.
ETA: It has provisions for a waist belt, I'm not sure where to get one that will work with it though.