I like the idea of a pack system. Plus there's no good reason not to use a checklist. Makes sure you have everything. Everything is in the pack, I can grab it and go. Except...

For my primary survival gear, my ten essentials+ list, I prefer to have my gear strapped, tied, or bolted to me. If I take off my pack, set it down, or become separated from it somehow, I still have my most important kit on me.

I'm not likely to lose this kit unless it's torn violently from me. Whereas with bags I have a tendency to set the bag down, and move away from it.

Of course some gear doesn't lend itself to being bolted to me. Extra clothes (socks, gloves, hat), water, and food don't tend to lend themselves to this system. These items I place in a pack. Other items I usually throw in a pack or bag, instead of tying to myself, are the repair kit, first aid kit, map, and compass. These items could be attached to me depending on the situation though.

My knife, flashlight, and fire starter I prefer to always have on me. Of course, this is as much for convenience as safety. I like just being able to reach for these items and have them. I don't want to have to search for these items when I need them.