Can one bag do it all? Yes, no, and maybe. It just depends on what your definition of "do it all" means. If you spend a lot of time in the outdoors, then I think you are looking at a backpack. Same thing with lots of travel. For business or workplace use I think the messenger or attache bags are better. I would hate to drag a tactical backpack into a meeting or have to hike with an attache bag slung over my shoulder.