I carry about 30 flies on my person, and have a few boxes in the car when I fish the river around here. I am generally only 5 minutes from the car but I have been thinking a lot like GRN lately and am going through what I want to carry with me. My fishing trips generally consist of 3 or 4 hours at a time and I find I am fishing one of 4 or 5 streamers (wooley buggers or sculpins, or wooley worms); 4 or 5 different nymphs (hares ear, caddis pupa, pheasant tail, scuds, prince) and 4 or 5 different dries (adams, elk hair caddis, ants, grasshopper, stonefly). put these together in various colors and a few different sizes and I am not sure there are any other flies I really need to carry. 15 to 20 patterns, 3 different colors (light, medium and dark browns for the dries/nymphs and white, tan or olive, and black for the buggers) and a few different sizes 12, 14, 16. and I thinnk this is my box I am putting together. I think I will leave some room for 4 or 5 flies that are the "hot flies of the week" either from the net here or the local fly shop. My biggest problem is I have been wearing a chest pack, and there is not a lot of room for fly boxes in it so I have to carry the flies in my shirt or wading jacket pocket, because of this, I need a couple small fly boxes for dries and nymphs and I put the streamers in the built in fly carrier in the chest pack.
I am going to continue to play around with this concept until I come up with something I really like, but that is it so far.
Dave