I bought a pair of orange waterproof Ortlieb classics and I'm very, very happy with them. It couldn't be easier. You simply pick the bag up directly off the rack via a handle and throw the shoulder strap over and off you go. There equally easy to put on and they are kept secure. They also come with internal zippered pouch -- but the more I ride with stuff -- the more I just skip the intricacies and toss it in there and go. Beautiful. Because of the simplicity and durability I know they will get used even if their initial buy in was a bit on the pricey side. Then again, if you buy a new bike -- strike while the iron is hot and bargain for a deal. I got 40% of mine which brought the overall cost in line with what I was hoping to get.