+1 for the Lowepro Flipside 400 AW. John suggested it for me a few years back and I still use it and love it! Of course, it's not as full as it used to be but even back then with all of my lenses in it, it was very comfortable to wear on my back during a hike. Being able to just slide it around to the front of me to change lenses without having to take it completely off & lay it on the ground was so quick and handy ...not to mention cleaner!