The kind like Tim has, with the padded seat and 3 seperate compartments for the back rack. Well then I get home and manage to talk myself out of them. I strapped a back pack to the rear rack and Cabellas has an over the tank bag for $10. I may return the big bags and settle for the smaller setup. I always buy crap and then get it home and change my mind. I just think the stuff I bought was too big.
I only use my bag for dirty tow straps, beer holder, and trash can. I have the lock and ride front rack so everything goes in it. When I did use it the sides are a pain because of the clasps and zipper set up. The rear one was the only one that I would use cause was easy to get into. The woman likes it so she has a seat so I had to put it on this Atv. I wanted the plastic one but them things are 150 plus. If you need storage on your bike And not spend a bunch of money these work fine and will keep your stuff dry and semi clean depending on dust. If I remember right I got mine from walmart for 40 bucks.
Sounds like the same kind of setup I have on the back, to me the canvas bags get old, if you get mud on the zipper and it dries while you're ridin it sucks. I've been lookin at some hard seat/bags for the back. I found a nice one on Ebay for about $250, whatever I get it's gotta have a seat or the woman won't be very happy with me, LOL. I like the bags other than that, and they tear if you have a bunch of stuff in there, I'm on my 4th one.