I agree - both with the "still searching" and the "it depends". Usually I have my Lowepro rolling bag with my flashes, 3 bodies and my 70-200 lens...one D600 has the 23-70 attached...other goodies (rain covers, filters, hoods, etc.) in the bag...200-400 in its own shoulder bag (came with the lens) and monopod attached to the shoulder bag...Monopod has attached holder for extra cards which also has my press pass, a lens cleaner and a business card holder with cards...Frequently I also have a large carabiener attached to the handle of the monopod as well - handy for keeping your camera and lens off the ground when you need two hands free...most places I shoot have chain link fence and I just attach to that...
Occasionally I'll take a smaller Lowepro backpack with a body and the two short lenses...Once in a great while - usually when it is really nice weather, I'll hook up what I want / need and just put the cameras on the back seat of the truck and then I'm rolling with only the gear...to reverse things, I frequently do the same but with only one camera, alrready in rain gear, when it is nasty weather out. Given an unknown shooting situation, I would take everything I could - less if it was hiking and more if I were going to a location where I could have a "home base" to work from where my gear was safe...
I rarely use filters and am sad to say that my current filter collection is way below what I'd like to have...but I have the basics...Back in the 80s I found one of the best tips on filters that I will pass on...Not doing it currently, but likely will when I eventually expand my filter collection. You would have to do this for each size of filter you have, but lets assume a 58mm for the example: Buy a 58mm screw in lens cap and a female of the same...screw your filters together with the cap on one end and the female on the other...it stacks in your bag like a lens and it is easy to pick a filter and put the others away. Much faster and easier than any other option I've found and I've tried many...If you buy all large filters and use step down rings, they can sit in on the side of the filter stack or fit another spot in your camera bag...