When I needed a handlebar bag for my touring bike in Germany last summer, I bought a small Vaude bag with a KlickLok mount. I originally mounted it on my touring bike, but I moved it to my commuter bike when I got back to the States. Since I wanted to be able to use a handlebar mounted light or a handlebar mounted camera, I rotated the bag down so it would not interfere with them.
As you can see for the images above, this had the additional advantage of both lowering the center of gravity of the bag and moving it closer to the steering axis. These moves improve the handling of the bike. It also makes the bag more useful for carrying things because the opening in the top of the bag is now at a 45 degree angle and things too large to fit in the bag can be inserted in the pouch formed by unzipping the back edge of the top. I have found this to be quite useful for carrying things like books and papers, as well as rolled up clothing items that are too large to fit in the bag.
Note the Koozie camera holder Gooped to the top of the Softride stem. I've found this works quite well for carrying a compact camera while riding. I can remove the camera from the koozie, turn it on, take one or more images while riding, turn it off and replace it in the koozie, all with one hand. The Kozie provide some protection for the camera and, on my touring bike, I've added a layer of foam between the Koozie and the top of the stem to help isolate the camera from vibration.