New to the forum, this really is a great wealth of info!
I work in the field so I take my BOBs with me everyday. In that sense you get an idea of the things you need, and things you will never need, so it is a constant weeding out process. I like the MOLLE because I can change out components that don't work well. I have a Maxpedition Jumbo side pack with the absolute essentials, that don't change, and I keep a Max falcon II bag (backpack) that I change out seasonal gear in.
Best mods, I attached a gerber brush thinner machete, these things are wicked, to the point of working as well as a much heavier axe, plus, make a great weapon in a pinch and incredibly light, another good one is to make mental note of where everything is, I keep the things I use the most, flashlights, fixed blade knife, med kit, bug spray/sunblock on the outside pockets for easy access. I keep the extra socks and rain gear in the main comp. since they are not used as often.
The system works well and the two bags don't interfere with each other. In addition, I have other packs for different situations...who said you cant have more than one BOB!
I have one question I would love input on: Since you can't carry enough water to last forever, are you better off having the very expensive filters or the small/compact water treatment pills?
Thanks!