I already have panniers and have several sizes of waterproof stuff sacks for camping. I plan on some weekend and overnight bike trips this summer and was wondering if there is any advantage to a trunk bag over a stuff sack and a couple of bungie cords. BTW, my tool kit and spare tube are carried in a triangle frame bag above the seat tube water bottle, so no worries about where it will go. My wife wants to get me something for cycling for my birthday and the two things I could think of were a trunk bag or a mini-frame pump.