A Bogen back pack where the 4x5 and dark cloth fits in the lower compartment. I carry one lens only, and that's in a padded box in a top compartment along with about six or seven film holders, cable release, and filters. My meter fits in one of the outside pockets along with cleaning wipes, a bottle of water, some sun screen, a level, and a stop clock. (although I have never managed to remember all of those items on any single trip, at least one thing is left behind).
I carry my tripod.
My camera is a wooden field camera from Fine Art Photo Supply, and it folds together very nicely.