I use an old but sturdy Samsonite Suitcase. I roll up a gear bag and put it inside to carry to the boat.
My thinking is, I don't want a bag that says "Steal me, I'm full of expensive scuba gear."
My Samsonite looks like a pauper's suitcase. (Obviously, when the bag starts falling apart I'll replace it.) I check my wing/harness, fins, knife, flashlight, mask and have enough room for some clothes as well. The only breakable items are the flashlight and mask. The mask is in it's own box which I roll up in a sweat shirt. The flashlight gets rolled up as well. I have a couple of heavy duty Home Depot trash bags (I think they're 5 mil) to wrap up anything that might still be wet when I travel home.
My regs always come on the plane with me, as does any camera equipment. If you have a knife attached to your gauges, make sure you check it. TSA won't let you bring it on the plane.
Finally, don't forget to get DAN insurance to cover your gear.