FWIW, I have an MSR backpack I found at a motorcycle shop. Has a compartment for tools, with little holders etc., room for a bladder, and enough room to hold my enduro jacket. MUCH better than trying to find a place on the bike, and get it to stay put with all the weight of tools etc. banging around.
I also have a tube bag that goes on the front fender. I carry a 3.00x21 tube, it will also work in the back in a pinch. Room for tire irons and a CO2 inflator kit. Kinda interferes with my headlight beam though. Meh.
Heb Dduw, heb ddim; Duw a digon
I'm that gun-totin', farm-raised, evangelical, pro-environment, OHV ridin'/drivin', Southern civil rights pro-labor Liberal yo' momma told you couldn't possibly exist.