Guitarcrazy,
I carry-on camera, lenses and most fragile components like optical view finder, strobes, memory cards, rechargeable batteries (you've got to carry-on these. Check with your airline, most don't want you to check batteries), and an iPad.... the rest, gets check. That would be everything... BC, wetsuit, boots, fins, pair of masks, regulator, pair of dive computers, flashlights, surface marker, small lights for night diving, everything else for the photo equipment like clamps, arms, mounts, ports, battery chargers, tools and of course, clothing and some flip-flops.
Occasionally when we open our checked luggage, that be arriving to our destinan or back home, we find a note from TSA or from some official entity that will say something like: This bag was inspected by on xyz by abc. Nothing has gone missing or been damaged.
I know we have been fortunate, and hope that will continue to be the case with future trips, and I wish the same to you. Enjoy your trip, have fun and let us know how it went.
Ricardo