[nigelH]

Hard boat - obviously. Kitting up for a deep dive on a RIB is a joke. Not even a funny joke.
O2 - obviously
Onboard Compressor - not significant to me
Teas/Coffees - on tap but push it into their hand when they get back.
Snacks - it has been nice when we could anchor up but not on a deep water trip.
Speed - not dog slow but don't fight this one.
Diver Lift - vertical, at the back
Deck Area - plenty
Shelter - handy but not vital
Toilet - obviously
Kitting up Bench - big, deep, solid and space for each to set up their kit before we ropes-off, space underneath for boxes/bags.
Emergency Cylinder & Reg on line - a drop tank? Very good, thinking skipper, a trapeze, even if it is just a 6m bar on a lazy shot is wonderful, quite simple and reasonably compact.
Dry Access & Egress from boat - obviously. AND have a door in the side. Don't ask me to clamber over a bar, in swell, with a twinset or rebreather on my back.
On board storage (overnight) - some people like it a lot for the weight belts, fins, rebreather stages et. al.
Basic scuba spares for sale - maybe but have duck tape, tie wraps and basic tools and just hand them out.
Diver Recall System (thunder flashes etc) - Be serious. Throw what you like in the water. If I have 30mins of stops to do I'm doing them.
fresh water wash down (deck shower/hose) - very nice. One live aboard said they eliminated tummy problems when they eliminated the mask dunk bucket for a push the button shower head on a hose. Squirting that in your face when you came back aboard was wonderful.

Divers, especially deep/deco divers, are at their most vulnerable when they just get back on board. They know they ought to take it easy but there are things they feel they have to do. Hit them with the TLC then and they won't remember it but they will have good vibes about you and that spreads by word of mouth. What the best boats have is that indefinable feeling that the skipper/crew are on your side. I know good boats that I can't fault but where I know I am just the weekend's job and, frankly, I feel no reason to go back.

Build any service into the price. Paying a couple of quid more you don't notice, being asked to find £1.80 at sea sucks. Similarly if 'selling' spares don't have a price list (except in your head) - keep up the image of being there to help and me paying to replace the one in your box of spares.