I've decided on a compromise between 3 different methods of organization. I have one all purpose box that contains a selection of my favorites. If I know the water well and/or I want to travel light, I can go out with just that box and do fine. If I don't know the water or feel like matching specific hatches and sizes will be important on a given day I have several boxes organized by species kind of Caddis, Midges, etc and then streamers and buggers, poppers. Then I also have boxes for species specific flies like steelhead, salt, and salmon. I pack my vest with leaders, floatant, tools and stuff like that and pack my fly boxes into 2 chest packs one for warm water and one for cold water. The boxes for streames, WB and some others move back and forth between the 2.