Would agree with Ross, shoulder bag would probably be limited to 1 body and a couple of lenses. I've had great use out of my Lowepro Phototrekker AW, fantastic bag, lots of space, very comfortable and comes with a day sac to put other bits and pieces in. Still got the Crumpler Brians Hot tub backpack, good bag, but prefer trekker, and hasn't got not as much space as trekker, but room for 17 inch laptop in separate pouch, but haven't got around to putting it up for sale yet.