Knowing this topic has been discussed already I still want to show how I do with my rig since I got recently a storm roller bag, in which I store the housing (Subal for S2 pro), the Subal Dome port for the 12-24 lens, a Nikonos SB-105 Flash and a Sealux Flash housing for Nikon SB-80DX and some accessories. The storm case is supposed as a carry-on. All my camera gear goes into a small Tamrac photobag. The Tamrac photobag can be attached onto the handle of the storm rollerbag and is also for carry
Finally I was able to take a picture from my backpack with the equipment. Much easier to explain how I pack my rig for air travel.
Total weight is 14.6 kg without computer and 16 kg with the computer. The backpack is a Lowepro Computer Trekker II.
Besides this, I take the remaining important equipment at my wife's carry-on: 8 inch dome port, port extensions, housing handles, chargers (camera, strobe batteries, dive lamps batteries, computer), vacuum pump, focus light, 2 buoya