I used to carry my housing and camera and regs and computer and laptop and all the stuff and by the time I get to where I am going my back, neck or shoulders are so messed up from lugging all that crap that my trip is not as enjoyable as it could be.
Now I just check two bags and everything except my laptop, DSLR, lens and dive computer gets checked, my ikelight housing is a pretty robust item, I wrap it in my 3 mil and just stuff it down in the middle of the bag.
I really enjoy underwater photography but have almost given it up because of the hassle of lugging all the equipment around.
This is my camera/computer bag,
Lowepro - CompuDaypack
I only use one lens underwater and for top side I have a small pocket sized camera
This is my second carryon/camera bag it usually has books, snacks and overflow room to spare for the trip home, I use it to carry my rig to and from the boat while on location.
Lowepro - Stealth Reporter D650 AW
By the way the last three times I have connected in Miami coming home from the Caribbean TSA has tried to forced me to check my camera bag because it wouldnt fit in the bag sizers at the entrance to the security screening. Just two weeks ago I wiggled it to make it drop in to the sizer and the TSA agent said it had to drop in on its own. I have only had this problem in Miami and only when having to rescreen after coming thru customs. Thankfully the first two times I got American involved and they battled with TSA to get me thru. This last time they let me go before I had to get American on their case.
I am close to breaking away from American just to avoid connecting in Miami, my least favorite airport in the world.
One last point the last two trips coming home from Belize and Grand Cayman the foreign security made me remove the batteries from my dive lights and carry them on they could not stay in my checked luggage