Here's my backpack. It's an
REI Wonderland. I chose it first because it fit me well. That's most important. No amount of gear badly carried is worth it. Fit first. Next I chose it because it's HUGE, almost 5000 cubic inches. If I fill it, I can't lift it. The next time, I won't worry about capacity. I also deliberately chose an external frame pack. They're a little heavier empty, but I can shift the weight around more comfortably with the external frame. The pack body rides on the frame and the frame then connects to my hips and shoulders through the hip belt and shoulder straps. An internal frame pack has those same pieces, sure, but the pack is hugging your back. I don't want or need that. I like to have it *off* my back as much as possible. It's cooler that way, and I don't need the more centralized center of gravity. I have a nice North Face internal frame at home--never use it.
The purple straps on the bottom are my own addition. I threaded some one inch nylon straps with fastex buckles through a couple of ladderlocks on one of the crossbars on the frame and snugged them down real tight. Now I have a "trunk". I installed the straps so that the female part of the buckle is on the top, which lets me pull downward on the free part of the strap to tighten. I'll probably have a picture here eventually with something installed in the "trunk".
On the picture I've labeled the main pockets and the regular stuff that goes there. Consistency in packing is rewarded with being able to find stuff easily. Or by feel. I often reach into my pack without getting out of my sleeping bag, and knowing where it was when I put it there is a big help.