I have to travel quite a bit for work assignments. Shortly after I bought my Bronica system, I bought a Delsey Pro 2 bag. Looking back, I should have bought the Pro 1, but I can still carry 2 bodies (1 with a speed grip attached), 4 lenses with hoods, 7 backs, a bunch of filters in both 67 and 77mm (I use stack caps), a Luna-Pro F, and gobs of film. If I really push it, I can get a third body in (with one of the lenses installed). When flying, I pack my Polaroid back, a small lightstand, and a tripod in my checked baggage.
I've found that I can get away with a rather small Bogen 3001 tripod with a 2025 head, but I prefer to use a 3021 with a 3047 head. 35mm gear travels in a Lowepro Nature Trekker backpack. I keep a mid-size Tamrac bag in my checked baggage so I don't have to work out of the backpack on location (if it's a PJ job). My flash equipment travels in checked baggage in a Graflex case from on old Speed Graphic to which I added some heavy padding. I carry a Metz 60CT1 with dry-fit, and extra dry-fit battery, charger, a Sunpak 544 with a Quantum Turbo & charger, a Newton bracket, an old Larsen 17" soft box form a soff-shoulder, and a bunch of small accessories.