One backpack. The UAP from Spec-Ops, as pictured. Hand made in Texas.
1730 cubic inches so 28.3 liters.
I use it for EDC, and since I can add or remove storage (as pictured), I also take it on day long hikes. Evidently you can fill it with 3 days worth of things which I have yet to do.
I'm 5'11'', 165 lbs. Average build.
The backpack is very comfortable and rigid. Tough, guaranteed for life. It also has straps for your hips, which you can't really see in the picture. Dedicated compartment for a water reservoir in the middle of the backpack, so you don't have some stupid ass lump on your back. It holds 3 liters easy. Think I'd even put a bigger reservoir in it.
http://www.specopsbrand.com/tactical-gear/multicam-tactical-gear/t-h-e-pack-ultimate-assault-pack-multicam.html 