When I say 'whole caboodle' I'm referring to ultra-lightweight dive kit where the only concession to extravagence is a pair of regulator sets and a set of twinning straps in case I need to push the boundaries a nad and 5kg of clothes.
5kg of clothes? Dive trips aren't fashion shows ya know? 1 pair speedos, 1 t-shirt and the clothes on your back is all you need 
The trick is to know your allowances and pack to them (maxing them out). But ultimately, if you really need something you have to take it, even if it means being over weight and paying. There is no point compromising your trip. I guess the difficulty is knowing what you really need. Most people whose bags are over weight don't use half the stuff in them.
I sometimes go one further and arrange for the group I'm travelling with to bring bits and pieces of spare equipment. I carry spare strobes or housing, someone else carries the arms, someone else the extra ports (+ adapter for different housings), lenses, camera bodies etc. Of course, the person who drowned his own camera managed to drown my strobe in the spare housing. But the system still works sometimes 