just back from 10 days away with 27kg's of luggage. I'll split it down into each bag.
dive bag
fins, mask, BC (Oceanic Probe weighing in at >4-5kg), primary reg set, back up reg set, spares kit, batteries, 2.5mm full length wetsuit (which I never wore), boardies, other shorts for nights, booties, thongs (flip flops/jandals, not the american definition!), sharkskin (Best thing I've ever bought!), hood, SMB + finger spool
carry on bag
T-Shirts, undies, 2 pair of ankle socks, primary and secondary torch, camera, case, strobe, 7" tablet, chargers, cables, 2 books and a very light high quality rain/wind jacket.
the more I dive, the less 'stuff' I take and the more diving spares and equipment I take. I washed and re-wore the same T-Shirt to the boat every day and wore my sharkskin pretty much all day every day on the boat. I think I took 5 teeshirts and 2 pair boardies and 2 pair proper cotton shorts + jeans and proper shirt for flying.
personal needs bag is the usual plus: sun screen, ear drops, eye drops, nose spray, cold tablets, contact lenses, good pair of clippers, insect spray
the only thing I regret not taking was a small towel or something for my camera while on the boat.